Sodium metabisulfite is commonly used as preservative in foods but can oxidize to sulfite radicals initiating molecular oxidation. Ghrelin is a peptide hormone primarily produced in the stomach and has anti-inflammatory effects in many organs. This study aimed to assess endogenous omega-3 (n-3) and omega-6 (n-6) polyunsaturated fatty acids (PUFAs) in rat peripheral organs following sodium metabisulfite treatment and determine the possible effect of ghrelin on changes in n-6 inflammatory pathway.Male Wistar rats included in the study were allowed free access to standard rat chow. Sodium metabisulfite was given by gastric gavage and ghrelin was administered intraperitoneally for 5 weeks. Levels of arachidonic acid , dihomo-gamma-linolenic acid , eicosapentaenoic acid  and docosahexaenoic acid  in liver, heart and kidney tissues were determined by an optimized multiple reaction monitoring (MRM) method using ultra fast-liquid chromatography (UFLC) coupled with tandem mass spectrometry (MS/MS). Cyclooxygenase (COX) and prostaglandin E2 (PGE2) were measured in tissue samples to evaluate changes in n-6 inflammatory pathway.Omega-6 PUFA levels, AA/DHA and AA/EPA ratio were significantly increased in liver tissue following sodium metabisulfite treatment compared to controls. No significant change was observed in heart and kidney PUFA levels. Tissue activity of COX and PGE2 levels were also significantly increased in liver tissue of sodium metabisulfite treated rats compared to controls. Ghrelin treatment decreased n-6 PUFA levels and reduced COX and PGE2 levels in liver tissue of sodium metabisulfite treated rats.Current results suggest that ghrelin exerts anti-inflammatory action through modulation of n-6 PUFA levels in hepatic tissue. Indeed,2 (TXB2) ,12.Ghrelin is an acylated peptide that stimulates the release of growth hormone (GH) from the anterior pituitary via binding to the GH secretagogue receptor (GHS-R) . Circula2S2O5 ingestion has not been investigated. This study was designed to determine changes in endogenous PUFA levels in rat peripheral organs and investigate whether ghrelin attenuates inflammatory pathways induced by Na2S2O5.Although studies have shown that sulfite exposure leads to increased arachidonic acid levels in alveolar macrophages, changes in liver, heart and kidney PUFA levels following Na2S2O5) (n = 10); rats treated with ghrelin (n = 10); rats treated with Na2S2O5 + ghrelin (n = 10). Control group received 1 ml/kg/day distilled water via gavage and 1 ml/kg/day saline via intraperitoneal injection as vehicle for 35 days. Sodium metabisulfite treated animals were given freshly prepared Na2S2O5 (100 mg/kg/day) solution via gastric gavage for 5 weeks as previously described [2S2O5 is efficiently absorbed at the given dose when administered via intragastric gavage and significantly increases plasma S-sulfonate levels [All experimental protocols conducted on rats were performed in accordance with the standards established by the Institutional Animal Care and Use Committee at Akdeniz University Medical School. Male Wistar rats weighing 350–450 g were housed in stainless steel cages and were allowed free access to water and standard rat chow  containing 6.05% crude fat which included linoliec acid, linolenic acid, saturated fatty acids and monounsaturated fatty acids. Animals were maintained at 12 h light–dark cycles and a constant temperature of 23 ± 1°C at all times. Rats were randomly divided into four experimental groups which included control (n = 8); rats treated with sodium metabisulfite , dihomo-gamma-linolenic acid , eicosapentaenoic acid  and docosahexaenoic acid  were purchased from Sigma-Aldrich . Deuterium labeled AA-d8 internal standard  was obtained from Santa Cruz Biotechnology . Solutions of AA, DGLA, EPA, DHA and AA-d8 standards were prepared in analytical grade methanol . An optimized multiple reaction monitoring (MRM) method was developed using ultra-fast liquid chromatography (UFLC) coupled with tandem mass spectrometry (MS/MS). A UFLC system  was coupled to a LCMS-8040 triple quadrupole mass spectrometer . Chromatographic separations were carried out using Inertsil HPLC column  maintained at 40°C. DHA, EPA, AA and DGLA were separated using a gradient elution with a flow rate of 0.45 ml/min. Mobile phase solvent A was 10 mM ammonium acetate  in water and solvent B was acetonitrile . Gradient program was solvent B, 70% (0 min), 90% (3 min), 100% (3.01-4 min) and 70 % (4.01-8 min). MRM transitions and responses were automatically optimized for individual compounds in negative electrospray ionization (ESI). In the negative ESI-MS mode the precursor and product m/z values for AA, DHA, EPA, DGLA and AA-d8 are given in the results section. Responses to AA, DHA, EPA and DGLA were optimized to a linear calibration range from 100 ng/ml to 30 ug/ml and a sample analysis time of 8 minutes.Samples were prepared for LC-MS/MS analysis via a modified protocol as previously described ,26. All ’,N’-tetramethyl-p-phenylenediamine (TMPD) at 590 nm. One unit of enzyme activity was defined as the amount of enzyme that caused the oxidation of 1 nmol of TMPD per minute at 25°C.Liver tissues were weighed and homogenized in 0.1 M ice-cold Tris–HCl buffer at pH 7.8 containing 1 mM EDTA. Tissue homogenates were centrifuged at 10,000 g for 15 minutes at 4°C and supernatants were kept at −80°C until assayed. Cyclooxygenase (COX) activity was measured using a COX activity assay kit  according to manufacturer’s instructions. The COX activity assay kit measures enzyme activity colorimetrically by monitoring the appearance of oxidized N,N,N2 (PGE2) was measured in tissue samples by a commercial enzyme immunoassay test kit  according to manufacturer’s instructions. Liver tissues were weighed and homogenized in 0.1 M ice-cold phosphate buffer at pH 7.4 containing 1 mM EDTA and 10 μM indomethacin. Tissue homogenates were centrifuged at 10,000 g for 15 minutes at 4°C and supernatants were kept at −80°C until assayed. Briefly, PGE2 present in the sample competes with acetylcholinesterase-labeled PGE2 antibody for binding sites on a goat polyclonal anti-mouse antibody. Following a wash to remove unbound materials, a substrate solution is added to the wells to determine the bound enzyme activity. The color development is stopped, and the absorbance is read at 412 nm. The intensity of the color is inversely proportional to the concentration of PGE2 in the sample. A standard curve of absorbance values of known PGE2 standards was plotted as a function of the logarithm of PGE2 standard concentrations (pg/ml) using the GraphPad Prism Software program for windows version 5,03. (GraphPad Software Inc). PGE2 concentrations in the samples were calculated from their corresponding absorbance values via the standard curve.Prostaglandin EProtein concentrations were measured at 595 nm by a modified Bradford assay using Coomassie Plus reagent with bovine serum albumin as a standard .Data were analyzed using Sigma Stat (version 2.03) statistical software for Windows, and a P value <0.05 was considered statistically significant. Statistical analysis for each measurement is described within the figure and table legends.2S2O5 (n = 10), 37,50 ± 9,79; Ghrelin (n = 10), 58,33 ± 12,25 and Na2S2O5 + Ghrelin (n = 10), 54,44 ± 14,88 grams.We have recorded the body weight of all animals during the 5 week experimental period. We have seen a significant increase in the weight of animals treated with ghrelin. This data is shown in Figure The precursor and product m/z values for analyzed PUFAs were as follows: DGLA C20: 3n6), precursor m/z: 304.80, product m/z: 59.00, 260.70; AA (C20: 4n6), precursor m/z: 303.10, product m/z: 59.00, 258.90; EPA (C20:5n3), precursor m/z: 301.10, product m/z: 59.10, 256.70; DHA (C22: 6n3): precursor m/z: 327.10, product m/z: 59.10, 283.20; AA-d8, precursor m/z: 311.10, product m/z: 59.10, 97.90, 267.10. Figure 0: 3n6, p2S2O5 + ghrelin groups  measured in experimental groups were as follows: Control, 3.06 ± 0.77; Na2S2O5, 7.43 ± 0. 29; Ghrelin, 3.72 ± 1.47 and Na2S2O5 + Ghrelin, 5.87 ± 0,90 U/mg protein.Total COX activity, as shown in Figure 2S2O5 + ghrelin treated groups. PGE2 levels (mean ± SD) measured in experimental groups were as follows: Control, 45,64 ± 16,91; Na2S2O5, 105,56 ± 29,90; Ghrelin, 43,40 ± 16,68 and Na2S2O5 + Ghrelin, 64,09 ± 6,96 pg/mg protein.Liver PGE2 levels, as shown in Figure 2S2O5 ingestion. This study makes the novel observation that ingestion of 100 mg/kg/day Na2S2O5 for 5 weeks results in significantly increased n-6 PUFA levels, AA/DHA and AA/EPA ratio in the liver and leads to significantly increased tissue activity of COX and PGE2 levels. It also shows that ghrelin decreases n-6 PUFA levels and reduces COX and PGE2 levels in liver tissue of sodium metabisulfite treated rats.To the best of our knowledge, this study is the first to measure endogenous DGLA (C20:3n-6), AA (C20:4n-6), DHA (C22:6n-3) and EPA (C20:5n-3) levels in rat peripheral organs following Na2 equivalents (SDE) and with reference to the reported theoretical yield of 67.39 % SO2 from Na2S2O5 [2S2O5/kg/day was equivalent to 67.39 mg/kg/day SO2. The Joint Expert Committee in the World Health Organization (WHO) has established an acceptable daily intake (ADI) level for sulfites which is reported to be 0.7 mg/kg body weight, expressed as SO2 [The dose of sulfite administered in this study was determined with reference to our previous studies designed to investigate the effects of high level of sulfite intake -24. The  Na2S2O5 ,28, the d as SO2 .2S2O5 is efficiently absorbed at the given dose (100 mg/kg/day) when administered via intragastric gavage and significantly increases plasma S-sulfonate levels in rats [Hepatic oxidation of exogenous sulfite is diffusion limited . That is in rats ,33.The observed increase in liver n-6 PUFA levels, AA/DHA and AA/EPA ratio support previous studies which have shown that long-term in vivo exposure to sulfite aerosols induces inflammatory reactions  and thatWe have seen that the given dose of sodium metabisulfite treatment caused no significant change in PUFA levels in heart and kidney tissues of rats while it increased DGLA C20: 3n-6) and AA (C20: 4n-6) levels in the liver. This discrepancy is likely to result from the metabolism of ingested sulfite. As stated previously, exogenous sulfites are presented to the liver’s biotransformation system for processing and elimination and their oxidation is diffusion limited [ and AA , DGLA (C20:3n-6), AA/DHA and AA/EPA ratio are significantly increased in rats following high level of sulfite intake and that sulfite ingestion leads to significantly increased liver activity of COX and PGE2 levels. We also show that ghrelin decreases n-6 PUFA levels and reduces COX and PGE2 levels in liver tissue of sodium metabisulfite treated rats. Further studies are needed to clarify mechanisms by which ghrelin regulates the n-6 inflammatory pathway in liver tissue.


White tetrakis(4-methylpyridinium) bis(4-methylpyridine)-γ-octamolybdate hydrate 2 crystallizes in space group C2/c with a = 27.086(4) Å, b = 11.917(2) Å, c = 19.332(2) Å, β = 124.427(1)º, Z = 4. Results of crystal structure determinations are presented and discussed in this paper. Thermal stability and decomposition studies of the obtained two new γ-octamolybdates were performed using TG/DSC and XRPD methods. Both compounds decomposed with the formation of 4-methylpyridinium β-octamolybdate. The two compounds are pseudo-polymorphs, exhibiting both striking similarities as well as significant differences in their structures and properties.We synthesized two new γ-octamolybdates, and determined their crystal structures from single-crystal X-ray diffraction data. Orange-yellow tetrakis(4-methylpyridinium) bis(4-methylpyridine)-γ-octamolybdate The online version of this article (doi:10.1007/s00706-014-1166-0) contains supplementary material, which is available to authorized users. According to the literature  = 2.668 Å), whereas N31 atoms form trifurcated bonds N31…O6, N31…O3, and N31-H…O13 with d(D..A) = 2.89, 3.01, and 3.169 Å, respectively. As can be expected, trifurcated H-bonds are weaker than single bonds created by atoms in a similar environment. Selected bond distances and details of hydrogen bonds are collected in Tables 8O26]4− fragment is surrounded by six methylpyridine moieties). What is interesting is that there are no H-bonds linking neighboring amines, as they are mutually interacting only by π–π interactions (shifted face-to-face). In the structure, one can find infinite channels , built of 4-methylpyridine moieties placed almost in parallel to each other in a distance of 3.8–4.25 Å. The γ-octamolybdate anions surrounded by cations form columns along the direction [100]  Å). Molecules of protonated amines are connected with octamolybdate anions through hydrogen bonds formed by nitrogen from 4-methylpyridine and oxygen atoms from γ-[Mo8O26]4−, and each one is directly connected to two molecules of amines by a nitrogen–molybdenum bond Mo1–N11 (2.255(2) Å). Figure 8O26]4− , a system of hydrogen bonds forming infinite layers parallel to (10-1) is observed. Rings (C21…C27) are arranged parallel to the plane (200), creating a double-layer build of 4-methylpyridine molecules.The unit cell of this compound contains four equivalent centrosymmetric γ-octamolybdate anions [Mo8O26]4− anions are arranged in planes (002) and also in planes parallel to (100), cutting an axis at ¼ and ¾. Organic molecules fill the space between the anions, forming strips parallel to the planes (002), intersecting the z axis at the 0, 0, ¼ and 0, 0, ¾ points 2]. In hydrated compound 2, water molecules enable the formation of infinite H-bonds network.As can be found in Table 3 . In compolybdate , a very 8O264− was also very important.Results of thermogravimetric studies were interpreted based on weight loss, and thus, only the qualitative, most probable explanations will be given. However, to clarify the processes of thermal decomposition of investigated γ-octamolybdates , we performed a synthesis of tetrakis(4-methylpirydine) β-octamolybdate , identic1 is shown in Fig. The thermal behavior of 4-methylpyridinium γ-octamolybdate(VI) 2) decomposes in three main stages  hydrate .The loss of water molecules in compound 1 is presented. It turns out that in the temperature range of 150–175 °C, compound 1 transforms into tetrakis(4-methylpyridine) β-octamolybdate , the thermal decomposition of anhydrous γ-octamolybdate lybdate , except that at 125 °C, both phases of γ- and β-octamolybdates are present, but at higher temperatures only the β isomer occurs. At temperatures of 225–300 °C, the amorphous phase is observed, and in the end MoO3 crystallizes.The decomposition process of 4-methylpyridinium octamolybdate(VI) −1 regions 4− were tested using the DFT method and the crystal structure parameters of 4-methylpyridinium γ-octamolybdate (1) and β-octamolybdate 4− anion, two Mo atoms are directly coordinated to N atoms from amines (Mo–N distances 2.24–2.32 Å). The negative charge of the anions is compensated by protonated amines. Gamma octamolybdates can be obtained as anhydrous 1 or hydrated salts 2.Two new γ-octamolybdates were obtained and characterized, one was synthesized in hydrothermal and one in ambient conditions. In the compounds investigated by us in each centro-symmetric γ-.CCDC 780058 and 780060 contain the supplementary crystallographic data for The stability of the octamolybdates at higher temperatures was investigated using TG/DSC studies. The analyses were carried out on a NETZSCH STA 409 Luxx instrument, at a heating rate of 25 °C/min in an air atmosphere.θ range was from 5° to 65° with a step size of 0.02°.Thermal decomposition studies were carried out using a Philips X`Pert Pro MPD powder diffractometer, equipped with a high-temperature chamber Anton Paar. X-ray data were collected at temperatures: 25, 50, 75, 100, 125, 150, 175, 200, 225, 250, 275, 300, 350, 400, and 25 °C again, and the 2IR measurements were performed on a Fourier and the vacuum spectrometer Bruker VERTEX 70 V. The samples were pressed into pellets with KBr and investigated at room temperature.In the literature, there are no published data clearly indicating the functionals that should be used in investigations of this type of compounds. It was decided, therefore, to carry out the calculations in parallel, using three functionals: Becke–Perdew (BP) –17, PerdSupplementary material 1 (DOC 6261 kb)Below is the link to the electronic supplementary material.


Kinetic analysis showed how tough the uncommon D-β-Asp residue was against the peptide bond cleavage as compared to natural L-α-Asp. Differences in pKa and conformation between L-α- and D-β-Asp side chains were plausible factors to determine reactivity of Asp isomers. The present study, for the first time, provides a rationale to explain less reactivity of D-β-Asp to allow abnormal accumulation.Although L-amino acids were selected as main constituents of peptides and proteins during chemical evolution, D-aspartyl (Asp) residue is found in a variety of living tissues. In particular, D-β-Asp is thought to be stable than any other Asp isomers, and this could be a reason for gradual accumulation in abnormal proteins and peptides to modify their structures and functions. It is predicted that D-β-Asp shows high resistance to biomolecular reactions. For instance, less reactivity of D-β-Asp is expected to bond cleavage, although such information has not been provided yet. In this work, the spontaneous peptide bond cleavage was compared between Asp isomers, by applying real-time solution-state NMR to eye lens αΑ-crystallin 51–60 fragment, S It is well known that L-amino acids were selected as main constituents of peptides and proteins during chemical evolution. However, D-amino acid residues have been found in a variety of living tissues12145731445It is predicted that racemization and isomerization of natural L-α-amino acids could modify the structure and function of various proteins. In fact, most of enzymes and receptors can recognize the difference in molecular chirality in a living body. There is also a possibility that biomolecular reactions are modified by the presence of unusual amino acid isomers. For instance, peptide bonds are spontaneously cut off at sites next to normal L-α-Asp and asparagine residues16171H NMR was applied for this purpose, to observe the cleavage reaction in real time. A human lens αΑ-crystallin 51–60 fragment, S51LFRTVLD58SG60 (αΑ51–60) and αΒ-crystallin 61–67 analog, F61D62TGLSG67 (αΒ61–67) composed of L-α- and D-β-Asp  the decrease in non-terminal L-α- or D-β-Asp58 as a reactant, (ii) the increase in C-terminal L- or D-Asp58 as a product, and (iii) the increase in N-terminal Ser59 of Ser59-Gly60 as another product. Similarly, the bond cleavage in αΒ61–67 sequence can also be monitored by (i) the decrease in non-terminal L-α-/D-β-Asp62 as well as non-terminal Thr63 as a reactant, (ii) the increase in C-terminal L- or D-Asp62 as a product, and (iii) the increase in N-terminal Thr63 of 63–67 fragment as another product. Utilizing the ability of high-resolution solution-state NMR to distinguish (i), (ii), and (iii) in real time, here we evaluate how fast the peptide bond cleavage proceeds in the presence of L-α- and D-β-Asp residues. The comparison demonstrates that both D-β-Asp isomers in αΑ51–60 and αΒ61–67 show high resistance to peptide bond cleavage, that may cause undesired accumulation of D-β-Asp residue in peptides and proteins with time.1H NMR spectra of αA-crystallin 51–60 fragment (αA51–60) containing L-α- or D-β-Asp58 isomers. In this work, each fragment was dissolved in acetate buffer/D2O (pD 4.0) and subject to NMR measurement at 70 °C. The conditions pD 4.0 and 70 °C were adopted to avoid undesired side reactions such as racemization and isomerization of Asp residue via a succinimide intermediate.Let us compare the 1H NMR spectra showed a difference between the peptides containing L-α- and D-β-Asp isomers. As indicated by the top spectrum (in black) in α proton signal of non-terminal L-α-Asp58 was observed at 5.1–5.0 ppm. The assignment was confirmed by the absence of the signal in a 51–58 fragment peptide, S51LFRTVLD58 containing C-terminal L-Asp58; see the bottommost spectrum (in green). For non-terminal D-β-Asp58, on the other hand, the Hα signal moved to 4.9–4.85 ppm; see the spectrum (in black) in α at 5.0–4.9 ppm; notice that the assignment of Phe53 Hα is confirmed by comparing 1H NMR spectra of αA51–60 and its derivative where Phe53 is substituted to Ala53  and Hα (around 4.95 ppm) were kept constant . Totally, the observed spectral changes show that the non-terminal L-α-Asp58 of αA51–60 was gradually converted to C-terminal L-Asp58, as a result of spontaneous peptide bond cleavage next to L-α-Asp58. It is emphasized that Asp58 residue is only the site for bond cleavage reaction. This was confirmed by HPLC elution profile that showed a product peak with masses ([M+H]+) of 950.5, the value consistent with the theoretical one of the 51–58 fragment, 950.53.β of N-terminal L-Ser59 because such peak was absent for the spectrum of 51–58 fragment (in green). Thus we can capture all the spectral changes associated with the peptide bond cleavage next to L-α-Asp58; (i) the decrease in non-terminal L-α-Asp58, (ii) the increase in C-terminal L-Asp58, and (iii) the increase in N-terminal L-Ser59 in panel A.When the peptide bond is cut off between Asp58 and Ser59, a dipeptide, Ser59-Gly60 is also produced. The production of Ser59-Gly60 leads to an increase in N-terminal Ser59 with time. In fact, a signal was observed at ~4.31 ppm (indicated by *in panel A) and increased with time. The signal is assignable to H1H NMR spectra of αA51–60 containing D-β-Asp58 were observed at pD 4.0 and 70 °C. In analogy with L-α-Asp peptide, the bond cleavage was analyzed in terms of (i) the loss of non-terminal D-β-Asp58, (ii) the increase in C-terminal D-Asp58, and (iii) the increase in N-terminal L-Ser59. As illustrated in α signal of non-terminal D-β-Asp58 (around 4.91 ppm) were slightly decreased as compared to the constant Phe53 Hα (around 4.95 ppm). However, no significant increase of the C-terminal D-Asp58 signal was found at around 4.87 ppm. This was evident from the comparison to the spectrum of 51–58 fragment peptide, S51LFRTVLD58 containing C-terminal D-Asp58, shown at the top (in green) of panel B. The result means that the peptide bond cleavage was limited by the presence of uncommon D-β-Asp58. If this is the case, the increase in N-terminal L-Ser59 should also be suppressed. Actually, the Hβ signal intensity of N-terminal Ser59 at 4.3 ppm (*in panel B) was less increased with time, as compared to the case of L-α-Asp58 isomers (panel A). All results show that the presence of uncommon D-β-Asp58 interferes with the spontaneous peptide bond cleavage, which may accumulate undesired D-β-Asp58 residue in the peptide.To examine whether peptide bond cleavage is modified by the presence of D-β-Asp58, the In the previous section, we have qualitatively demonstrated that uncommon D-β-Asp58 in αA51–60 shows high resistance to peptide bond cleavage next to Asp. To quantify how D-β-Asp residue interferes with the bond cleavage reaction, we determined the rate constants of the bond cleavage at L-α- and D-β-Asp58 by using real-time signal intensity changes of reactants and products. The kinetic analysis is valid because NMR signal intensity is proportional to the concentration of each reactant and product in the present cleavage reaction.α signal of C-terminal L-Asp58 at 4.85 ppm as well as the intensities of N-terminal Ser59 Hβ at 4.3 ppm, as described in the Methods section. The result was plotted as filled squares (L-Asp58) and triangles (Ser59) in α signal of non-terminal L-α-Asp58 at 5.1–5.0 ppm. Because Hα signal of non-terminal L-α-Asp58 was partly overlapping with Hα of Phe53 at around 4.95 ppm, the loss of non-terminal L-α-Asp58 was quantified by subtracting constant (time-independent) intensity of Phe53 Hα from the sum of the Hα signal intensities of non-terminal L-α-Asp58 and Phe53, and plotted as open squares in First, the increase in the cleavage products of L-α-Asp peptide was quantified by using the integral intensities of Hα signal of the non-terminal D-β-Asp58 was severely overlapping with Phe53 (α at 5.02 ppm (filled black circles) were found to be consistent with those from integral intensities (open squares), as shown in Next, to quantify how D-β-Asp modifies the peptide bond cleavage, the signal intensities of αA51–60 consisting of D-β-Asp58 were also analyzed as a function of time. Because Hth Phe53 , the relth Phe53 . This esThe comparison of time-dependent intensity changes between L-α and D-β peptides demonstrates that the reactivity of D-β-Asp residue to peptide bond cleavage is different from that of L-α-Asp. As shown in Now let us focus on the rate constants for spontaneous peptide bond cleavage at L-α- and D-β-Asp58. When the cleavage reaction is treated as first-ordered, the rate of the product increase follows the rate equation as:Cter] is the concentration of a product, C-terminal Asp58 or N-terminal Ser59, and [Cnon] is the concentration of a reactant, non-terminal Asp58, respectively. k is the rate constant for the bond cleavage reaction at L-α- and D-β-Asp58. According to Cter] are given byCnon]0 is the initial concentrations of non-terminal L-α- and D-β-Asp58. Thus the rate constant k can be determined by fitting k were estimated to be (6.9 ± 0.5) × 10−3 h−1 for L-α-Asp and (2.2 ± 0.4) × 10−3 h−1 for D-β-Asp residue. The reactivity of uncommon D-β-Asp was less than one-third of natural L-α-Asp in an αA-crystallin fragment.In 61D62TGLSG67 (αB61–67), composed of L-α- and D-β-Asp62 as a second model sequence. In the previous section, we showed that D-β-Asp58 residue was less reactive to the peptide bond cleavage as compared to natural L-α-Asp58 in an αA-crystallin fragment. Such less reactivity of D-β-Asp keeps D-β-peptide stable and that is a plausible reason for gradual accumulation of D-β-Asp with age. To confirm the hypothesis, we have compared the cleavage kinetics of an αΒ-crystallin 61–67 derivative, F1H NMR spectra of αB61–67 composed of L-α- and D-β-Asp62 were compared. The Hα region of L-α- and D-β-Asp62 was also expanded in α signal of non-terminal L-α-Asp62 around 5.1 ppm was decreased and converted to C-terminal L-Asp62 around 4.85 ppm (red arrow). At the same time, the doublet assigned to N-terminal Thr63 methyl at 1.66 and 1.64 ppm, indicated by *in In For D-β-Asp62 in αB61–67 sequence, the peptide bond cleavage was found to be slower than L-α-Asp62. As shown in k of (1.3 ± 0.2) × 10−3 h−1 as compared to (4.7 ± 0.9) × 10−3 h−1 for L-α-Asp62, that is obtained by fitting The time-dependent concentration changes in Ka of L-α- and D-β-Asp side chain carboxyl is different from each other. In fact, it has been previously reported that pKa of β-Asp side chain carboxyl group is 3.3 at 60 °C, lower than the value of α-Asp, 4.0Ka of Asp carboxylic side chain is thought to explain the difference in the cleavage rate between Asp isomers.As described in the previous section, we demonstrated that uncommon D-β-Asp was less active to peptide bond cleavage (degradation) than L-α-Asp residue. Here we consider why such difference in reactivity was found in L-α- and D-β-Asp residues. Judging from that peptide bond cleavage proceeds via a cyclic anhydride intermediate51LFRTVLD58SG60, as shown in the bar charts in CO) of Asp58 peptide bond is nucleophilically attacked by hydroxyl oxygen of carboxylic side chain (OOHCO), a cyclic anhydride intermediate is formed; (ii) another fragment Ser59-Gly60 is also cleaved as a result of intramolecular cyclization; and (iii) the 51–58 fragment including C-terminal Asp58 is finally produced by hydrolyzing cyclic anhydride intermediate; see the reaction scheme in CO and OOHCO interferes with the nucleophilic attack of OOHCO on CCO to initiate intramolecular cyclization  observed for the protonated precursor ions of αA51–60 and αB61–67 were 1094.6 and 696.1. These values were consistent with the theoretical ones, 1094.58 and 696.32, respectively.Isomers of αA51–60 and αB61–67 composed of L-α- and D-β-Asp residues were synthesized by Fmoc solid-phase chemistry using an automated solid-phase peptide synthesizer (Shimadzu PSSM-8). Fmoc-amino acids from Watanabe Chemical Industries  were used. Crude peptides were purified by RP-HPLC using a C18 column  with a linear gradient of 10–60% (for αA51–60) and 5–55% acetonitrile (for αB61–67) for 60 min in the presence of 0.1% TFA at a flow rate of 3.0 mL/min with monitoring at 215 nm. HPLC grade solvent was used to confirm the purity of the peptide. The purity of each peptide was confirmed to be >98% by RP-HPLC and MALDI-TOF MS or ESI-MS. The masses ([M+H]1H-NMR measurements were carried out on 400 MHz spectrometer (JEOL ECA400) equipped with a super-conducting magnet of 9.4 T. A high sensitivity probe  for 10-mm diameter tube was used to obtain good S/N ratio. About 3 mg of αA51–60 and αB61–67 consisting of L-α- or D-β-Asp residue was dissolved in 4 ml of 50 mM acetate buffer/D2O (pD 4.0) and subject to NMR measurement at 70 °C. D2O of 99.9% atom D from ISOTEC (USA) was used. The real-time measurements started immediately after the thermal equilibrium was attained. Free induction decays (FIDs) were accumulated at 512–1024 times, corresponding to 1–2 h intervals. The digital frequency resolution was set to 0.3 Hz. Although D2O was selected as a solvent, the DANTE presaturation pulse sequence was applied to avoid the signal overlapping of impurity light water (HDO) with the target 1H NMR peak. The spectra were processed by the JEOL DELTA software. Chemical shift of the 1H NMR signal was obtained by referring to the absorption frequency of acetic acid in the solvent.Real-time α and Ser59 Hβ was used. First, the amount of cleavage product, 51–58 fragment containing L-Asp was evaluated by using the integral intensities of the signal assigned to C-terminal L-Asp58 at 4.85 ppm and those of N-terminal Ser59 at 4.3 ppm, both relative to the initial concentration of the reactant. The loss of the reactant was evaluated by integral intensities of the non-terminal L-α-Asp58 signal at 5.1–5.0 ppm. Because the signal was partly overlapping with that of Phe53 at around 4.95 ppm, the concentration of non-terminal L-α-Asp58 was quantified by subtracting constant (time-independent) intensity of Phe53 Hα from the sum of the integrated signal intensities of non-terminal L-α-Asp58 and Phe53 from 5.08 to 4.91 ppm. Here, the integrated signal intensity corresponding to one proton of Phe53 was justified by using ring proton signal of Phe53 at 7.7–7.5 ppm corresponding to five protons. The intensities of non-terminal L-α-Asp58 were also estimated from the peak height at 5.02 ppm.Concentrations of reactant and product peptides were quantified by using integral intensities and/or peak heights of the respective NMR signals. For αA51–60, the signals of Asp58 Hα signal at 4.91 ppm because the signal was severely overlapping with C-terminal D-Asp58. Since the signal of C-terminal D-Asp58 at 4.85 ppm was weak and overlapped with non-terminal D-β-Asp58, the amount of C-terminal D-Asp58 was replaced by the concentration of N-terminal Ser59, obtained by integrating Hβ peak at 4.33–4.27 ppm.For non-terminal D-β-Asp58, the intensities were estimated from the peak height of Hα, and by the doublet shape as a result of vicinal spin-spin coupling between methyl protons and the side chain proton. On the other hand, the loss of the reactant was evaluated by integral intensities of Hα of non-terminal L-α- and D-β-Asp62 at 5.14–5.06 and 4.99–4.91 ppm, respectively, as well as methyl signal of non-terminal Thr63 at 1.57–1.51 ppm.For αB61–67, the amount of the cleavage product was analyzed by using the integral intensity of methyl signal of N-terminal Thr63 in 63–67 fragment at 1.67–1.62 ppm. The assignment of Thr63 methyl signal was confirmed by the signal intensity that was three times as large as Asp H+) and gauche- (G−)) of αA51–60 and αB61–67 composed of L-α- and D-β-Asp residues was evaluated from vicinal spin-spin coupling constants Hα-Hβ1 (Jαβ1) and Hα-Hβ2 (Jαβ2) obtained by high-resolution 1H NMR measurement at 10 °C. Here, the temperature was as low as 10 °C to avoid undesired bond cleavage and intramolecular cyclization throughout the measurement. The detailed procedures are described elsewhereThe population of staggered side-chain conformers (trans (T), gauche+ , P(G+), and P(G−) were calculated from the following equationsProbabilities, Jt and Jg are the vicinal spin-spin coupling constants between α- and β-protons in pure T and G conformers. Jt (13.56 Hz) and Jg (2.60 Hz) were referred to Pachler’s parameter setHow to cite this article: Aki, K. and Okamura, E. D-β-aspartyl residue exhibiting uncommon high resistance to spontaneous peptide bond cleavage. Sci. Rep.6, 21594; doi: 10.1038/srep21594 (2016).


The crystal structure of the title compound displays boat and half-chair configurations of the thiazine ring. 18H18N2O2S.0.375H2O, has two independent organic molecules (A and B) and 3/4 of a water molecule distributed over three sites. In molecule A, the 1,3-thiazine ring is in a boat conformation, with the C atoms at the 2- and 5-positions out of the plane. The angle between the two phenyl rings is 51.70 (12)°. In molecule B, the thiazine ring is in a half-chair conformation, with the S atom forming the back of the half-chair. The angle between the two phenyl rings is 84.44 (14)°. The A molecule features an intramolecular N—H⋯O hydrogen bond, which closes an S(5) ring motif. In the crystal, the corresponding N—H grouping of the B molecule participates in an intermolecular hydrogen bond to the A molecule. The A molecule participates in a C—H⋯O interaction back to the B molecule, whilst the B molecule features an intramolecular C—H⋯O link, which generates an S(10) loop.The asymmetric unit of the title compound, C N-[phenylmethylidene]aniline with 3-sulfanylpropanoic acid to produce 2,3-diphenyl-2,3,5,6-tetrahydro-4H-1,3-thiazin-4-one 2C=NH imines has been reported -promoted cyclization of A, the ring takes a boat configuration with the groups at the 2- and 5-positions pseudo-equatorial and the hydrogens at these positions within 1.993 Å of each other. The stability gained by having both groups pseudo-equatorial must offset the higher energy expected in a boat conformation. The dihedral angle between the C1- and C8-benzene rings is 51.7 (2)°. An intramolecular N2—H2N⋯O1 hydrogen bond is observed, which closes an S(5) ring.The two independent organic molecules in the asymmetric unit exhibit different geometries for the thiazine ring Fig. 1. In molB, the thiazine ring adopts a half-chair conformation. The groups at the 2- and 5-positions cannot readily be defined as pseudo-axial or pseudo-equatorial, but the phenyl ring at the 2-position is closer to axial, while the amide group at the 5-position is closer to equatorial. The dihedral angle between the phenyl rings (C20–C25 and C26–C31) is 84.4 (2)°. This conformation is similar to that observed for 2,3-diphenyl-2,3,5,6-tetrahydro-4H-1,3-thiazin-4-one  loop.In molecule The residual electron density suggested several solvent molecule sites but only with partial occupancies. The best model fixed the occupancy for each of the three water-molecule sites at 0.25.B (corresponding to the one involved in the intramolecular N2—H2N⋯O1 hydrogen bond in molecule A) participates in an intermolecular N4—H4N⋯O2 hydrogen bond to molecule A . Tetrahydrofuran (2.3 ml) was added, the solid dissolved, and the solution was stirred. Pyridine  was added and then N-acetyl-l-cysteine  was added. Finally, 2,4,6-tripropyl-1,3,5,2,4,6-trioxatriphosphorinane-2,4,6-trioxide (T3P) in 2-methyltetrahydrofuran  was added. The reaction was stirred at room temperature. TLC (EtOAc) after one day showed the reaction was complete, with two product spots, but the reaction was allowed to stir another 13 days. The mixture was poured into a separatory funnel with dichloromethane and distilled water. The layers were separated and the aqueous was then extracted twice with dichloromethane. The organics were combined and washed with saturated sodium bicarbonate and then saturated sodium chloride. The organic was dried over sodium sulfate, and concentrated under vacuum to a solid. The crude was chromatographed on 30 g flash silica gel, eluting with 50% ethyl acetate/hexanes and 100% ethyl acetate. Fractions containing the larger, more polar spot on TLC were combined, concentrated under vacuum, recrystallized from ethyl acetate/hexanes, and rinsed with ethanol to give light-yellow crystals of N-acetamide . m.p.: 460–463 K. Rf = 0.24 (EtOAc). Colourless cuboids were grown by slow evaporation from 2-propanol. The fractions containing the other TLC spot [Rf = 0.33 (EtOAc)] showed four different compounds by NMR, including the title compound.A two-necked 25 ml round-bottom flask was oven-dried, cooled under NUiso(H) = 1.2Ueq(C). The three solvent molecule sites were given occupancy of 0.25 each, as that proved to be the best way to account for the residual electron density.Crystal data, data collection and structure refinement details are summarized in Table 210.1107/S2056989014026425/hb7315sup1.cifCrystal structure: contains datablock(s) I. DOI: 10.1107/S2056989014026425/hb7315Isup2.hklStructure factors: contains datablock(s) I. DOI: Click here for additional data file.10.1107/S2056989014026425/hb7315Isup3.molSupporting information file. DOI: Click here for additional data file.10.1107/S2056989014026425/hb7315Isup4.cmlSupporting information file. DOI: 1037009CCDC reference:  crystallographic information; 3D view; checkCIF reportAdditional supporting information:


The first five-membered group-VI 3-ferrocenyl heterocycle bearing a further aromatic substituent at the 1′ position of the ferrocene backbone is reported. 9H6BrS)(C13H7F6)], consists of a ferrocene backbone with a bis(trifluoromethyl)phenyl group at one cyclopentadienyl ring and a thiophene heterocycle at the other cyclopentadienyl ring. The latter is disordered over two sets of sites in a 0.6:0.4 ratio. In the crystal structure, intramolecular π–π interactions between the thienyl and the phenyl substituent [centroid–centroid distance 3.695 (4) Å] and additional weak T-shaped π–π interactions between the thienyl and the phenyl-substituted cyclopentadienyl ring [4.688 (6) Å] consolidate the crystal packing.The molecular structure of the title compound, [Fe(C For the disordered part , however, the distance of 3.871 (6) Å is too long for a π–π interaction caused by the increased torsion angle between the substituents in the 1- and 1′-position . The mean planes of the cyclopentadienyl rings and the bonded aromatic rings are almost coplanar with each other  and thus, a nearly parallel arranged stacking between the phenyl and the thiophene rings [8.9 (3)° for the main part and 9.7 (6)° for the other part] is realized.The title compound contains one molecule in the asymmetric unit with an intramolecular π–π distance between the centroids  to 56.6 (9)°, Speck et al., 2012et al., 2011et al., 2003et al., 2004et al., 2000et al., 2000et al., 2010et al., 2003et al., 1991et al., 2010et al., 1993et al., 2003The only reported examples of 3-ferrocenyl-substituted five-membered group-VI heterocycles phenyl)ferrocene with 3,4-dibromothiophene phenyl)ferrocene was prepared according to synthetic methodologies reported by Speck  al. 2014. The synC,C-cross-coupling reaction, 1-bromo-1′-phenyl)ferrocene  was dissolved in 50 ml of tetrahydrofuran (THF) and 1.2 equivalents  of a 2.5 M solution of n-butyllithium in n-hexane were added dropwise at 193 K. After 1 h of stirring at this temperature, 1.2 equivalents  of [ZnCl2·2THF] were added in a single portion. The reaction was kept for 10 min at this temperature and was then allowed to warm to 273 K during an additional hour. Afterwards, 0.25 mol% of [P(t-C4H9)2C(CH3)2CH2Pd(μ-Cl)]2 and 1.5 equivalents  of 3,4-dibromothiophene were added in a single portion. The resulting mixture was stirred for 10 h at 323 K. After evaporation of all volatiles, the crude product was dissolved in 30 ml of dichloromethane and was washed twice with 50 ml portions of water. The organic phase was dried over MgSO4 and the solvent was removed with a rotary evaporator. The remaining orange solid was purified by column chromatography on silica gel using a n-hexane/diethyl ether 1/1 (v/v) mixture. Red crystals of (I)n-hexane/methanol 1/5 (v/v) solution at ambient temperature. Yield: 660 mg phenyl)ferrocene). IR : ν = 1275 , 1504 , 1615  2848, 3095 . 1H NMR : δ = 7.61 , 7.09 , 6.90 , 4.73 , 4.69 , 4.46 , 4.25 . 13C{1H} NMR : δ = 140.64 , 135.56 , 131.54 , 125,63 , 124.88 , 123.50 , 121.12 , 119.05 , 109.78 , 82.98 , 82.01 , 71.40 , 70.17 , 68.81 , 68.20 . HRMS : C23H16F6FeSO: m/z = 557.9291 .Synthesis of (I)Uiso(H) = 1.2Ueq(C) and a C—H distance of 0.93 Å for the aromatic protons. The thienyl and the attached cyclopentadienyl ring were refined as disordered over two sets of sites with occupancies of 0.6 and 0.4. The spatial proximity of the sulfur and the bromine atom of the disordered part required DFIX  instructions, which were used for the minor disordered part (′-labeled). For both disordered parts, some anisotropic displacement ellipsoids were rather elongated and hence SIMU/ISOR restraints  I, new_global_publ_block. DOI: 10.1107/S1600536814020674/wm5048Isup2.hklStructure factors: contains datablock(s) I. DOI: Click here for additional data file.10.1107/S1600536814020674/wm5048Isup3.pngSupporting information file. DOI: 1018554CCDC reference:  crystallographic information; 3D view; checkCIF reportAdditional supporting information:


H-chromene-4-one moiety (r.m.s. deviation = 0.0191 Å) by 10.53 (8)°. In the crystal, molecules are linked by pairs of O—H⋯O hydrogen bonds, forming inversion dimers with an The title compound is relatively planar with the benzene ring being only slightly twisted with respect to the mean plane of the 4 19H18O3, were obtained by the reaction of hydroxyacetophenone and 4-tert-butylbenzaldehyde with hydrogen peroxide as oxidant. The plane of the benzene ring is slightly twisted to the mean plane of the 4H-chromene-4-one moiety (r.m.s. deviation = 0.0191 Å) by 10.53 (8)°. In the crystal, molecules are linked by pairs of O—H⋯O hydrogen bonds, forming inversion dimers with an R22(10) ring motif. The dimers are linked via C—H⋯π interactions, forming sheets parallel to (10-1).Yellow–green fluorescent crystals of the title compound, C H-chromen-4-one (common name: 3-hydroxyflavone) and its derivatives are present in a wide variety of plants as phytochemical compounds  is twisted by 10.53 (8)° with respect to the benzene ring (C10–C16). This relative planarity typical of the structural features of flavonols is reinforced by two intramolecular (C11—H11⋯O3 and C15—H15⋯O2) short contacts  ring motif.The molecular structure of the title compound is illustrated in Fig. 1s Table 1. These id Table 1 with an via pairs of O—H⋯O hydrogen bonds, forming inversion dimers with an In the crystal of the title compound, molecules are linked f Table 1. The dimet al., 1986para-substituted phenyl derivatives, such as the 4-aminophenyl derivative  in ethanol (2 ml) and aqueous NaOH . The mixture was stirred at room temperature overnight. Then dilute acetic acid (30%) was added to the reaction mixture with stirring until the mixture was acidic and was cooled with an ice bath. The mixture was stirred for an additional 30 min at 273 K, and the solid precipitate obtained was collected by filtration. Hydrogen peroxide  was then added to an ice-cold suspension of the precipitate in ethanol (5 ml) and aqueous NaOH . The mixture was allowed to warm to room temperature and stirred for 4 h. The mixture was then acidified with dilute HCl , and the precipitate formed was collected by filtration. Recrystallization from methanol gave yellow–green fluorescing crystals. Plate-like crystals suitable for X-ray diffraction analysis were obtained by slow evaporation of a solution in dichloromethane. 1H NMR : δ 1.33 , 7.46 , 7.50 , 7.79 , 8.13 , 9.50 . 13C NMR  δ 31.4, 35.1, 118.8, 121.8, 125.1, 125.8, 128.0, 129.0, 134.1, 139.3, 146.0, 153.2, 155.0, 173.3. Fluorescent emission maxima : λem = 525 nm.The title compound was prepared by a modification of the procedure described by Qin  al. 2008. 2-HydrUiso(H) = 1.5Ueq for the methyl and hydroxyl H atoms and 1.2Ueq(C) for other H atoms.Crystal data, data collection and structure refinement details are summarized in Table 210.1107/S2056989015011482/su5150sup1.cifCrystal structure: contains datablock(s) global, I. DOI: 10.1107/S2056989015011482/su5150Isup2.hklStructure factors: contains datablock(s) I. DOI: Click here for additional data file.10.1107/S2056989015011482/su5150Isup3.cmlSupporting information file. DOI: 1406583CCDC reference:  crystallographic information; 3D view; checkCIF reportAdditional supporting information:


N-salicylideneglycinato(2-) Schiff base ligand  and having the general formula K[Ln2(H2O)2]∙H2O (1–6), where Ln stands for Gd, Tb, Dy, Ho, Er and Tm, was prepared using the one-pot template synthesis. The complexes were thoroughly characterized by elemental and Thermogravimetric/Differential Thermal Analyses (TG/DTA), Fourier Transform Infrared Spectroscopy (FT-IR), and photoluminescence spectroscopies, electrospray-ionization mass spectrometry, and their magnetic properties were studied by temperature-dependent dc magnetic measurements using the superconducting quantum interference device (SQUID). The X-ray structure of the terbium(III) complex (2), representing the unique structure between the lanthanide complexes of N-salicylideneamino acids, was determined. The results of spectral and structural studies revealed the isostructural nature of the prepared complexes, in which the lanthanide ion is octacoordinated by two O,N,O-donor salgly ligands and two aqua ligands. The analysis of magnetic data confirmed that the complexes behave as paramagnets obeying the Curie law. The results of photoluminescence spectral studies of the complexes showed the different origin in their luminescent properties between the solid state and solution. An antenna effect of the Schiff base ligand was observed in a powder form of the complex only, while it acts as a fluorophore in a solution.A series of anionic heavy lanthanide complexes, involving the  Oh lysine , 6-aminoh lysine , phenylah lysine , tyrosinh lysine , glutamih lysine , aspartih lysine , valine h lysine ,20, leuch lysine , glutamih lysine , alanineh lysine , and glyh lysine ,22,23,24N-salicylideneglycine (1–6) were prepared by the one-pot template synthesis from the reaction mixture, containing one molar equivalent of lanthanide acetate (Ln(ac)3·xH2O, where Ln = Gd, Tb, Dy, Ho, Er, Tm, and x = 0–6), three molar equivalents of potassium hydroxide, two molar equivalents of 2-hydroxybenzaldehyde  and two molar equivalents of glycine (Gly) (3·xH2O + 20 mmol Gly + 30 mmol KOH in 25 mL) and salicylaldehyde solution in 96% ethanol (20 mmol in 25 mL) were mixed together and stirred at 60 °C for 1 h. Crystals, suitable for X-ray structure analysis in the case of complex 2, were formed by the slow cooling of the dark yellow solutions to laboratory temperature overnight.The lanthanide complexes of ne (Gly) . Concret1–6, formed by the cooling and slow evaporation of the reaction mixture, were filtered off, washed with 96% ethanol (2 × 5 mL) and dried in a desiccator over KOH. The final products were characterized by elemental analysis, Thermogravimetric/Differential Thermal Analysis (TG/DTA), Fourier Transform Infrared Spectroscopy (FT-IR) and photoluminescence spectroscopy, mass spectrometry, dc magnetic measurements using the superconducting quantum interference device (SQUID), and by single crystal X-ray structural analysis in the case of the terbium complex 2.Crystals of complexes 1: Potassium [diaqua-bisgadolinate(III)] monohydrate.Characterization of complex Yellowish microcrystals (yield η = 83%).18H20N2O9KGd (Mr = 604.707): C, 35.75; H, 3.33; N, 4.63. Found: C, 35.76; H, 3.40; N, 4.55%.Elemental analysis  for C−1), signal intensities are defined as w = weak, m = medium, and s = strong: 3338m ν(O–H), 3048s ν(C–H)arom, 2905m ν(C–H)aliphatic, 1627s ν(C=N), 1559s, 1543s νasym(COO), 1469m ν(C=C)arom, 1447m νsym(COO), 1301m ν(C–O)arom, 1068w δ(C–H)arom, 756m δ(H–C–H).FT-IR , signal intensities are defined as w = weak, m = medium, and s = strong: 461w ν(Gd–O), and 411m ν(Gd–N).Far-IR : 512.15 [Gd2]−, 530.18 [Gd2(H2O)]−, 577.11 [Gd2(H2O)(OH)+K]−, 642.15 [Gd2(H2O)(OH)+K+2CH3OH]−.Electrospray-ionization mass spectrometry measured in methanol solutions terbiate(III)] monohydrate.Characterization of complex Yellowish microcrystals (yield η = 92%).18H20N2O9KTb (Mr = 606.382): C, 35.65; H, 3.32; N, 4.62. Found: C, 35.75; H, 3.18; N, 4.42%.Elemental analysis  for C−1), signal intensities are defined as w = weak, m = medium, and s = strong: 3333m ν(O–H), 3048s ν(C–H)arom, 2902m ν(C–H)aliphatic, 1627s ν(C=N), 1558s, 1542s νasym(COO), 1470m ν(C=C)arom, 1447m νsym(COO), 1300m ν(C–O)arom, 1066w δ(C–H)arom, 755m δ(H–C–H).FT-IR , signal intensities are defined as w = weak, m = medium, and s = strong: 460w ν(Tb–O), and 411m ν(Tb–N).Far-IR : 513.10 [Tb2]−, 531.00 [Tb2(H2O)]−, 561.87 [Tb2(OH)+K]−, 610.81 [Tb2(H2O)(OH)+K+CH3OH]−.Electrospray-ionization mass spectrometry measured in methanol solutions dysprosiate(III)] monohydrate.Characterization of complex Yellow microcrystals (yield η = 82%).18H20N2O9KDy (Mr = 609.957): C, 35.44; H, 3.30; N, 4.59. Found: C, 35.20; H, 3.50; N, 4.61%.Elemental analysis  for C−1), signal intensities are defined as w = weak, m = medium, and s = strong: 3330m ν(O–H), 3049s ν(C–H)arom, 2900m ν(C–H)aliphatic, 1628s ν(C=N), 1557s, 1542s νasym(COO), 1470m ν(C=C)arom, 1445m νsym(COO), 1300m ν(C–O)arom, 1067w δ(C–H)arom, 755m δ(H–C–H).FT-IR , signal intensities are defined as w = weak, m = medium, and s = strong: 461w ν(Dy–O), and 413m ν(Dy–N).Far-IR : 518.13 [Dy2]−, 536.14 [Dy2(H2O)]−, 575.10 [Dy2(H2O)(OH)+Na]−, 583.11 [Dy2(H2O)(OH)+K]−.Electrospray-ionization mass spectrometry measured in methanol solutions holmiate(III)] monohydrate.Characterization of complex Yellowish microcrystals on sunlight, Pale orange microcrystals under the fluorescence light (yield η = 80%).18H20N2O9KHo (Mr = 612.387): C, 35.30; H, 3.29; N, 4.57. Found: C, 35.17; H, 3.18; N, 4.20%.Elemental analysis  for C−1), signal intensities are defined as w = weak, m = medium, and s = strong: 3334m ν(O–H), 3048s ν(C–H)arom, 2905m ν(C–H)aliphatic, 1629s ν(C=N), 1565s, 1544s νasym(COO), 1469m ν(C=C)arom, 1447m νsym(COO), 1300m ν(C–O)arom, 1067w δ(C–H)arom, 756m δ(H–C–H).FT-IR , signal intensities are defined as w = weak, m = medium, and s = strong: 461w ν(Ho–O), and 414m ν(Ho–N).Far-IR : 519.13 [Ho2]−, 537.13 [Ho2(H2O)]−, 576.06 [Ho2(H2O)(OH)+Na]−, 584.12 [Ho2(H2O)(OH)+K]−.Electrospray-ionization mass spectrometry measured in methanol solutions erbiate(III)] monohydrate.Characterization of complex Yellow microcrystals (yield η = 90%).18H20N2O9KEr (Mr = 614.716): C, 35.17; H, 3.28; N, 4.56. Found: C, 35.01; H, 3.23; N, 4.27%.Elemental analysis  for C−1), signal intensities are defined as w = weak, m = medium, and s = strong: 3338m ν(O–H), 3048s ν(C–H)arom, 2905m ν(C–H)aliphatic, 1629s ν(C=N), 1560s, 1542s νasym(COO), 1470m ν(C=C)arom, 1449m νsym(COO), 1301m ν(C–O)arom, 1068w δ(C–H)arom, 756m δ(H–C–H).FT-IR , signal intensities are defined as w = weak, m = medium, and s = strong: 460w ν(Er–O), and 415m ν(Er–N).Far-IR : 520.13 [Er2]−, 538.01 [Er2(H2O)]−, 578.14 [Er2(H2O)(OH)+Na]−, 585.14 [Er2(H2O)(OH)+K]−.Electrospray-ionization mass spectrometry measured in methanol solutions tuliate(III)] monohydrate.Characterization of complex Yellow microcrystals (yield η = 78%).18H20N2O9KTm (Mr = 616.391): C, 35.07; H, 3.27; N, 4.54. Found: C, 34.83; H, 3.14; N, 4.25%.Elemental analysis  for C−1), signal intensities are defined as w = weak, m = medium, and s = strong: 3331m ν(O–H), 3049s ν(C–H)arom, 2905m ν(C–H)aliphatic, 1629s ν(C=N), 1561s, 1542s νasym(COO), 1471m ν(C=C)arom, 1448m νsym(COO), 1300m ν(C–O)arom, 1068w δ(C–H)arom, 755m δ(H–C–H).FT-IR , signal intensities are defined as w = weak, m = medium, and s = strong: 461w ν(Tm–O), and 417m ν(Tm–N).Far-IR : 523.13 [Tm2]−, 541.13 [Tm2(H2O)]−, 588.07 [Tm2(H2O)(OH)+K]−.Electrospray-ionization mass spectrometry measured in methanol solutions (2(H2O)2]∙H2O (2) is depicted in 2O6 donor set. The coordination polyhedron can be described as biaugmented trigonal prism J50 software ). The poacts see , thus foR/S)-aspartato)europiate(III) tetrahydrate  clusters with the combination of different coordination polyhedra, and, thus, it cannot be used as a suitable reference.To the best of our knowledge, there are only three structures of lanthanide complexes involving the Schiff bases derived from aromatic 2-hydroxy-aldehydes and amino acids, and deposited within the Cambridge Structural Database  . The firahydrate , in whicric acid . It form1–6 is shown in The overview of FT-IR spectra of the prepared lanthanide complexes 1–6, which contained the similar diffraction positions  and isotopic distribution, to the molecular anionic species [Ln2]− in all the measured spectra, accompanied by a rich variety of pseudomolecular species derived from these anions, such as [Ln2(H2O)]−, [Ln2(H2O)(OH)+Na]−, [Ln2(H2O)(OH)+K]−, and [Ln2(H2O)(OH)+K+xCH3OH]−, where x = 1–2, respectively.The analysis of electrospray-ionization mass spectra, measured in the negative ionization mode (a representative example of the mass spectra of the dysprosium complex ex = 350 nm). The background-corrected emission photoluminescence spectra of the complexes 1–6 are shown in The photoluminesce spectra of the studied lanthanide complexes in solid state and in water solutions were measured in the visible spectral region under ultraviolet A (UVA) light excitation (λ(a)1, complex 6);the spectrum showing a broad peak (complex (b)2);the spectrum showing several narrow peaks (complex (c)3–5).the spectrum showing a combination of both broad and narrow peaks  spectral regions  is thermally stable up to ca. 220 °C and then a sharp weight loss accompanied by an exo-effect with the maximum centred at ca. 280 °C, associated with the decomposition of the complex connected with the Schiff base ligand’s oxidation, is apparent from TG/DTA curves. Further, the complex intermediate is decomposed in two waves and the thermal decay is not finished even at 976 °C. A plateau occurs between 643 and 772 °C, which may be connected with the formation of holmium(III) carbonate, Ho2(CO3)3, containing a small amount of an unidentified impurity , which starts to decompose to a mixture of holmium oxides at ca. 820 °C.The simultaneous TG and DTA analyses were performed for complex mple see . The com1–6) in the quest to describe their magnetic properties. As it turned out, this task is very complicated due to the effects of magnetic anisotropy found in the Ln3+ ions with unevenly filled 4f-orbitals and the effects of the crystal field of the ligands. Therefore, we decided to present here the results obtained by fitting the experimental data into an idealized model based on the Curie law with an added molecular field term using Hamiltonian in the form The solid state temperature dependence of magnetic susceptibility was measured over the temperature range of 300–1.8 K for all the prepared complexes , which is a fingerprint of the non-uniform Bolztmann population of the J-multiplet energy levels split by the crystal field. Such a splitting term can be described by a set of Stevens operators in the form.Theory of the magnetism of 4predicts  that forIts eigenvalues were calculated for 120 grids over one hemisphere, and the corresponding partition function, magnetization, and susceptibility were averaged. The results obtained are presented in the All chemicals were purchased from commercial sources  and were used as received without any further purification. The purity and composition of the prepared complexes were confirmed by means of elemental analysis, thermal analysis, electrospray-ionization mass spectrometry (ESI–MS), and FT-IR spectroscopy, and single crystal X-ray structure analysis.Elemental analyses (CHN) were performed on a Flash 2000 CHNO-S Analyser .-1 in a dynamic air atmosphere (50 mL·min−1). Powder X-ray diffraction (XRD) data were obtained using a MiniFlex 600 diffractometer , with Cu Kα1,2, in the range of 2–30 °2θ, with the scan speed of 2 °/min.The thermogravimetric analysis and differential thermal analysis (TG/DTA) were performed using the Exstar 6000 thermal analyzer  by heating the samples up to 1000 °C at the rate of 5 °C·min−1) and the Nujol technique in the Far-IR spectral region (150–600 cm−1). The reported FT-IR signal intensities were defined as w = weak, m = medium, and s = strong.FT-IR spectra were recorded on a Nexus 670 FT-IR spectrometer  using KBr pellets (400–4000 cmv/v) of the complexes were obtained by an LCQ Fleet ion trap mass spectrometer  in the negative ionization mode using the electrospray ionization (ESI–) technique. The thermal dependence of magnetic susceptibility measurements of the compounds were performed on an MPMS XL-7 SQUID magnetometer  in the temperature range of 300–1.8 K with an external field set to 0.1 T. The diamagnetic corrections were made by using the Pascal constants method by means of the MaTra2 software ∙H2O (1–6), where Ln stands for Gd, Tb, Dy, Ho, Er and Tm, was prepared. The complexes were thoroughly characterized, including single crystal X-ray analysis of complex 2. The results of temperature-dependence of magnetic susceptibility showed that the complexes behave as paramagnets obeying the Curie law with an added molecular field term. In the case of complexes 2–5, the precision of data fitting was influenced by crystal field effects. Thus, these complexes could be magnetically interesting as such, or as the reactants to form the 3d-4f systems, which could show the properties of molecular magnets. The analysis of photoluminescence data measured in the solid phase and in water solutions uncovered the blocking mechanism of the solvent on the energy transfer between the Schiff base ligands and the lanthanide central atom. This feature might be interesting for the production of selective solid-phase sensors.A series of six anionic heavy lanthanide(III) bis(


The present paper reports crystallographic studies on three related compounds that were of interest as precursors for synthetic and mechanistic work in organosulfur chemistry, as well as to model nitrogen-protecting groups. N-methylcarbamoyl)(trichloromethyl)disulfane, C3H4Cl3NOS2, (1), (N-benzylcarbamoyl)(trichloromethyl)disulfane, C9H8Cl3NOS2, (2), and (N-methyl-N-phenylcarbamoyl)(trichloromethyl)disulfane, C9H8Cl3NOS2, (3). Their molecular structures, with similar bond lengths and angles for the CCl3SS(C=O)N moieties, are confirmed. Compounds (1) and (3) both crystallized with two independent molecules in the asymmetric unit. Classical hydrogen bonding, as well as chlorine-dense regions, are evident in the crystal packing for (1) and (2). In the crystal of (1), molecules are linked via N—H⋯O hydrogen bonds forming chains along [110], which are linked by short Cl⋯Cl and S⋯O contacts forming sheets parallel to (001). In the crystal of (2), molecules are linked via N—H⋯O hydrogen bonds forming chains along [001], which in turn are linked by pairs of short O⋯Cl contacts forming ribbons along the c-axis direction. In the crystal of (3), there are no classical hydrogen bonds present and the chlorine-dense regions observed in (1) and (2) are lacking.The present paper reports crystallographic studies on three related compounds that were of interest as precursors for synthetic and mechanistic work in organosulfur chemistry, as well as to model nitrogen-protecting groups: ( These result in chlorine-dense regions of the crystal structure  consists of pairs of hydrogen-bonded dimers about an inversion center. The molecules in each dimer are linked by NH⋯O=C hydrogen bonds  has no available classical hydrogen bonding and lacks the chlorine-dense regions of (1) and (2). Of the two conformations available for (3), it is noteworthy that the four sulfurs of two adjacent molecules of (3b) are positioned in a parallelogram  with intermolecular contact distances of 3.5969 (8) Å, slightly less than the sum of their van der Waals radii; no such configuration is evident for molecules of (3a). Fig. 7A—H9AA⋯O1B and C9B—H9BA⋯O1A, with H⋯C contact distances 2.55 and 2.54 Å, C⋯O distances of 3.360 (3) and 3.432 (3) Å, and C—H⋯O angles of 143 and 157°] connect (3a) and (3b) molecules. Two additional non-classical hydrogen bonds  are shown.Compound (8H6N(C=O)S]2) disulfane S]2) disulfane     plus (5), shown in the top pathway of Fig. 86), a thiocarbamate salt, is typically made by reaction of carbonyl sulfide (COS) with a primary or secondary amine HNR1R2. Therefore B+ is usually the appropriate ammonium counter-ion H2N+R1R2. Finally, several variations of acylation chemistry are summarized in the bottom pathway of Fig. 8et al.  = 0.85 (1)Å. H atoms attached to C were idealized . In all cases, Uiso(H) = x × Ueq(Host), x = 1.2 except for methyl groups, where x = 1.5.Crystal data, data collection and structure refinement details are summarized in Table 510.1107/S2056989015015893/bg2565sup1.cifCrystal structure: contains datablock(s) 1, 2, 3. DOI: Click here for additional data file.10.1107/S2056989015015893/bg25651sup2.cdxSupporting information file. DOI: 10.1107/S2056989015015893/bg25651sup8.hklStructure factors: contains datablock(s) 1. DOI: Click here for additional data file.10.1107/S2056989015015893/bg25652sup3.cdxSupporting information file. DOI: 10.1107/S2056989015015893/bg25652sup9.hklStructure factors: contains datablock(s) 2. DOI: 10.1107/S2056989015015893/bg25653sup10.hklStructure factors: contains datablock(s) 3. DOI: Click here for additional data file.10.1107/S2056989015015893/bg25653sup4.cdxSupporting information file. DOI: Click here for additional data file.10.1107/S2056989015015893/bg25651sup8.cmlSupporting information file. DOI: Click here for additional data file.10.1107/S2056989015015893/bg25652sup9.cmlSupporting information file. DOI: Click here for additional data file.10.1107/S2056989015015893/bg25653sup10.cmlSupporting information file. DOI: 1420526, 1420527, 1420528CCDC references:  crystallographic information; 3D view; checkCIF reportAdditional supporting information:


OUCMDZ-3434 associated with the marine algae, Enteromorpha prolifera. Compounds 1 and 2 are two new α-glucosidase inhibitors with the Ki/IC50 values of 16.8/19.7 and 6.0/8.3 μM, respectively. In addition, the absolute configurations of wailupemycins D (3) and E (4) are also resolved in this paper for the first time.Wailupemycins H ( Diabetes mellitus is a clinical syndrome caused by genetic factors and environmental factors and characterized by high levels of blood glucose. For the past few years, the incidence of diabetes increased rapidly, and the diabetes treatment has become a global health problemStreptomyces sp. OUCMDZ-3434 associated with the marine green algae, Enteromorpha prolifera, exhibited significant α-glucosidase inhibitory activity at 50 μg/mL. Chemical study lead to the identification of two new epimeric polyketides that we named wailupemycins H (1) and I (2) with an unusual carbon skeleton coupled two 6-pyrane-2-one nuclei into a methylene linkage, along with the known wailupemycins D (3)4),5)Marine is believed to be a natural treasure house for medicine, and natural products of marine microbial origin play an increasingly important role in drug diescovery673 and 4 were identical to those of wailupemycins D3, ent-3  and E (4) were thus elucidated as - and -, respectively. The 15R- configuration of 3 was confirmed by Horeau’s method1112S-enantiomeric excess of 2-PHA. To analyze the results, the quantum calculation of molecular energies on the products of 3 with 2R- and 2S- PHA (3a and 3b) was carried out by the time-dependent density functional theory (TD-DFT) method at the B3LYP/6-31G(d) level3a is lower than 3b.  was obtained as yellow, amorphous powder. Its molecular formula was determined as C43H30O11 by the HRESIMS peak at m/z 723.1847 [M + H]+. Analysis of the 1H and 13C NMR data (1 contained α-pyrone and monosubstituted benzene residues similar to those of wailupemycins91014153)5)2-methine signals  attributed to α-pyrone moieties of wailupemycins D (3) and G (5) were both disappeared  were present  to C-1 (δC 164.9), C-2 (δC 100.2), C-1′ (δC 164.7), and C-2′ (δC 100.5) (1) was identified. The relative configuration of 1 was established by NOESY experiment (δH 3.63) and H-17 (δH 7.48) to H-6 (δH 4.71) and from H-17 (δH 7.48) to H-14a (δH 3.63) indicated the anti-orientation of the pyrone and phenyl moieties, suggesting the same relative configuration as 31  was determined by ECD calculations of the simplified model compounds I  and ent-I  using TD-DFT method at the B3LYP/6-31G(d) level1 is matched well with the calculated ECD for I and opposite to that of ent-I (Wailupemycin H (NMR data  indicateappeared . Instead present . In addiC 100.5) . Thus, tperiment . Key NOEof ent-I .2) was also C43H30O11 from the HRESIMS peak at m/z 723.1847 [M + H]+, indicating an isomer of 1. The similar UV, IR and 1D NMR spectra  and HO-15 (δH 6.07), and between H-4 (δH 5.67) and H-21 (δH 7.39), indicating the same cis-orientation of the pyrone and phenyl moieties as wailupemycin E (4)δH 4.28) and H-14a (δH 2.92) indicated a 6-epimer. This deduction was confirmed by ECD calculations of the simplified model compounds II  and ent-II  using TD-DFT method at the B3LYP/6-31G(d) level2 to the calculated ECD for II and the opposition to ECD of ent-II -configuration of 2.The molecular formula of wailupemycin I . The intermediate a further reacted with 5 or its enolate anion via a Michael addition to yield the keto-tautomer (b) of 1 that formed the more favorable enol-tautomer 1. By the same procedure, the bio-reactions between compounds 4 and 5 produced compound 2  as a substrate17181–5 exhibited stronger inhibitions of α-glucosidase and lower cytotoxicity than acarbose with the IC50/CC50 values of 19.7/279.8, 8.3/1317.2, 988.7/2750.0, 392.5/2975.3, and 239.3/2953.8, respectively . The selectivity indexes (SI) of compounds 1–5 were 14.2, 158.5, 2.8, 7.6, and 12.3, respectively. The results indicated that the aromatization of cyclohexanone moiety and the 6,15-cis-orientation of the pyrone and phenyl moieties tend to increase the α-glucosidase inhibitory activity and decrease the cytotoxicity of these compounds. In addition, a study of enzyme kinetics indicated that 1 and 2 were competitive α-glucosidase inhibitors with the Ki of 16.8 and 6.0 μM, respectively . HRESIMS data were recorded using a Q-TOF ULTIMA GLOBAL GAA076 LC mass spectrometer. HPLC and semi-preparative HPLC were performed using a Cholester column  and an ODS column , respectively. TLC and column chromatography (CC) were performed on plates precoated with silica gel GF254 (10−40 μm) and over silica gel  and Sephadex LH-20 (Amersham Biosciences). Vacuum-liquid chromatography (VLC) used silica gel H .Optical rotations were measured with a JASCO P-1020 digital polarimeter. UV data were recorded with a Beckman DU 640 spectrophotometer, and CD data were collected using a JASCO J-815 spectropolarimeter. IR spectra were taken on a Nicolet NEXUS 470 spectrophotometer as KBr disks. Streptomyces sp. OUCMDZ-3434 was isolated from E. prolifera collected from the Zhanqiao Beach , Qingdao, China in July 2012. The E. prolifera (1 g) were clipped and ground suspending in sterile distilled water. And then serially diluted to 1 mg/mL, 100 μL of which was deposited on a Gause’s synthetic agar plate containing chloramphenicol (100 μg/mL) as a bacterial inhibitor and incubated at 28 °C for 8 days. A single colony was transferred onto another Gause’s synthetic agar plate and was identified according to its morphological characteristics and 16S rRNA gene sequences (GenBank access No. KJ818249). A reference culture is maintained in our lab. at −80 °C. Working stocks were prepared on Gause’s synthetic agar slants and stored at 4 °C.The actinobacterial strain 2HPO4 0.5 g, MgSO4 0.5 g, CaCO3 2 g, and 1 L of old sea water, pH nature). The flasks were incubated on a rotatory shaker at 180 rpm and 28 °C for 8 days. 45 L of whole broth was extracted with equal volumes of EtOAc for three times. The EtOAc extract was concentrated under reduced pressure to give a dark brown gum (28.0 g).Spores were directly inoculated into 500 mL Erlenmeyer flasks containing 150 mL fermentation media consisted of glucose 20 g, beef extract 3 g, yeast extract 10 g, soluble starch 10 g, peptone 10 g, K2Cl2 (1:1 and 0:1) and then with MeOH–CH2Cl2  to give eight fractions (Fr1–Fr8). Fr2–Fr5 (4.68 g) were combined and separated on a HP20SS column, eluting with a stepwise gradient of MeOH–H2O  to give six fractions (H1–H8). Fraction H4 (403.5 mg) was subjected to a Sephadex LH-20 column eluting with MeOH to give four fractions (H4-1 to H4-4). Fraction H4-3 (38.1 mg) was further purified by HPLC on ODS  to yield 4 . Fraction H5 (121.3 mg) was subjected to a Sephadex LH-20 column eluting with MeOH to give three fractions (H5-1 to H5-3). Fraction H5-2 (31.2 mg) was further purified by HPLC on ODS  to yield 3 . Fraction H6 (243.7 mg) was also subjected to a Sephadex LH-20 column eluting with MeOH to give four fractions (H6-1 to H6-4). Fraction H6-2 (73.6 mg) was further purified by HPLC on ODS  to yield 5 . Fraction H6-3 (47.7 mg) was subjected to another Sephadex LH-20 column eluting with MeOH and further purified by HPLC on ODS  to yield 1  and 2 .The EtOAc extract (28 g) was subjected to a silica gel VLC column, eluting with a stepwise gradient of petroleum ether–CH25D +18.1 ; UV (MeOH) λmax (logε) 208 (4.49), 260 (4.18), 334 (3.82) nm; CD  λmax (Δε) 206 (−1.28), 235 (+0.48), 256 (−0.31), 311 (+0.06) nm; IR (KBr) νmax 2922, 1704, 1677, 1571, 1198, 699 cm−1; 1H and 13C NMR data, see m/z 723.1847 [M + H]+ .yellow, amorphous powder; [α]25D −39.6 ; UV (MeOH) λmax (logε) 208 (4.49), 260 (4.18), 334 (3.82) nm; CD  λmax (Δε) 229 (−0.31), 257 (+0.28), 291 (−0.73), 337 (+0.04) nm; IR(KBr) νmax 2922, 1704, 1677, 1571, 1198, 699 cm−1; 1H and 13C NMR data, see m/z 723.1847 [M + H]+ .yellow, amorphous powder; [α]25D +16.4 ; UV (MeOH) λmax (logε) 216 (3.53), 256 (3.12), 333 (1.57) nm; CD  λmax (Δε) 212 (+0.1), 224 (+0.97), 263 (−0.2), 289 (+0.57) nm; 1H and 13C NMR data, see m/z 365.2 [M + H]+.yellow, amorphous powder; [α]25D −28.6 ; UV (MeOH) λmax (logε) 215 (3.51), 256 (3.23), 332 (1.48) nm; CD  λmax (Δε) 231 (−0.73), 258 (+0.5), 285 (−1.31), 329 (+0.11)nm; 1H and 13C NMR data, see m/z 365.2 [M + H]+.yellow, amorphous powder; [α]3  in dry pyridine(1.5 mL), racemic 2-phenylbutyryl chloride  was added. The reaction mixture was stirred at r.t. for 36 h. Water (3.0 mL) was then added and the mixture was allowed to stand for 30 min. The solution was extracted with EtOAc (3 × 10 mL) after adjusting the pH value to 9 by dropwise addition of NaOH (0.1 M). The aqueous layer was acidified to pH 3 using HCl (1 M) and then extracted with CH2Cl2 (3 × 10 mL). Evaporation of the CH2Cl2 solution gave the unreacted 2-PHA (5.3 mg) with [α]25D +5.8 , indicating the S- enantiomeric excess.To a solution of 3  and 5  in EtOH (1 mL) was added 1.85% formaldehyde solution  that was prepared by dilution of 37% HCHO aqueous solution with EtOH. The reaction mixture was heated at 80 °C for 3 h. HPLC analysis revealed three products one of which was identified as 1 by ESIMS peak at m/z 723.3 [M + H]+ and co-HPLC with the natural-1   with 5  and 1.85% formaldehyde , and was identified by co-HPLC with the natural-2  along with the ESIMS peak at m/z 723.2 [M + H]+ (To a solution of  column) . By the [M + H]+ .μL of the sample solution, 20 μL of PBS and 20 μL of 2.0 mm p-nitrophenyl-α-D-glucopyranoside (pNPG) solution (in phosphate buffer) were mixed in a 96-well microplate and incubated at 37 °C for 5 min. A volume of 10 μL of α-glucosidase diluted to 0.2 U/mL by 0.01 M PBS was then added to each well. After incubating at 37 °C for 15 min, the absorbance at 405 nm was recorded by a Spectra max 190 micro plate reader (Molecular Devices Inc.). The blank was prepared by adding phosphate buffer instead of the α-glucosidase and the acarbose was used as a positive control. Blank readings (no enzyme) were subtracted from each well and results were compared to the control. The inhibition (%) was calculated as [1 − (ODdrug/ODblank)] ×100%. The IC50 value was calculated as the compound concentration that is required for 50% inhibition and the IC50 value of the acarbose was 1.12 mM.The inhibitory effects were assayed as described preciously1 and 2 against α-glucosidase activity was measured with increasing concentrations of pNPG  as a substrate in the absence and presence of 1 and 2 at 34.6 and 69.2 μM, and 17.3 and 34.6 μM, respectively. Optimal amounts of compounds 1 and 2 used were determined based on the enzyme inhibitory activity assay. Mode of inhibition of 1 and 2 were determined by Lineweaver-Burk plot analysis of the data that were calculated by Michaelis-Menten kinetics.According to the paper182 and 95% air at 37 °C. Cell suspension, 100 μL, at a density of 2 × 104 cell mL−1 was plated in 96-well microtiter plates and and exposed to different concentrations of compounds in triplicate for 72 h. The initial concentrations of compounds were 2 mg/mL in DMSO, and then were diluted into 625, 125, 25, 5, and 1 μg/mL with RPMI-1640 medium, respectively. The experiments were divided into blank control, testing compounds and the positive control groups, and each group was set up three parallels. Then, 10 μL of PBS containing MTT  was added to each well. After 4 h incubation at 37 °C, the supernatant was removed and 200 μL of DMSO was added to each well to solubilize the formazan crystals. After vigorous shaking, absorbance values were measured in a microplate reader  at 570 nm. The cytotoxicity was represented at these concentrations as [(ODblank − ODdrug)/ODblank × 100%]. The CC50 value, defined as the compound concentration necessary to induce cell cytotoxicity by 50%, was calculated by SPSS  v19.0 software.The cytotoxicity on murine small intestinal IEC-6 cells were assayed by MTT  methodThe calculations were performed by using the density functional theory (DFT) as carried out in the Gaussian 033132343536How to cite this article: Chen, Z. et al. New α-glucosidase inhibitors from marine algae-derived streptomyces sp. OUCMDZ-3434. Sci. Rep.6, 20004; doi: 10.1038/srep20004 (2016).


E)-1-[diazenyl]naphthalen-2-ol ligands, forming a slightly distorted square-planar environment. In the isotypic nickel(II) and palladium(II) complexes, the metal atoms are located on centres of inversion, hence the metal coordination spheres have perfect square-planar geometries.In the title copper(II) complex, the metal atom is coordinated by two N atoms and two O atoms from two bidentate ( E)-1-[diazenyl]naphthalen-2-olato}copper(II), [Cu(C16H8Br3N2O)2], (I), the metal cation is coordinated by two N atoms and two O atoms from two bidentate (E)-1-[diazenyl]naphthalen-2-olate ligands, forming a slightly distorted square-planar environment. In one of the ligands, the tribromobenzene ring is inclined to the naphthalene ring system by 37.4 (5)°, creating a weak intramolecular Cu⋯Br interaction [3.134 (2) Å], while in the other ligand, the tribromobenzene ring is inclined to the naphthalene ring system by 72.1 (6)°. In the isotypic nickel(II) and palladium(II) complexes, namely bis{(E)-1-[diazenyl]naphthalen-2-olato}nickel(II), [Ni(C16H8Br3N2O)2], (II), and bis{(E)-1-[diazenyl]naphthalen-2-olato}palladium(II), [Pd(C16H8Br3N2O)2], (III), respectively, the metal atoms are located on centres of inversion, hence the metal coordination spheres have perfect square-planar geometries. The tribromobenzene rings are inclined to the naphthalene ring systems by 80.79 (18)° in (II) and by 80.8 (3)° in (III). In the crystal of (I), molecules are linked by C—H⋯Br hydrogen bonds, forming chains along [010]. The chains are linked by C—H⋯π interactions, forming sheets parallel to (011). In the crystals of (II) and (III), molecules are linked by C—H⋯π interactions, forming slabs parallel to (10-1). For the copper(II) complex (I), a region of disordered electron density was corrected for using the SQUEEZE routine in PLATON [Spek  complex, bis{(Spek 2015. Acta Cr N,O-bidentate chelation to stabilize transition or main group metal complexes. Azo-metal chelates have also attracted increasing attention due to their interesting electronic and geometrical features in connection with their applications in molecular memory storage, non-linear optical elements and printing systems. Another advantage of complexes involving azo DNO’s (dyes and pigments) and transition metal ions is the possibility to obtain new compounds with biological activity 2·H2O, and Pd(OAc)2·H2O. We report herein on the synthesis and crystal structures of the title complexes, (I)–(III), of the ligand (E)-1-[diazenyl]naphthalen-2-ol, whose crystal structure has been described previously -1-[diazenyl]naphthalen-2-ol 4 value of 0.15 naphthalen-2-olato)copper(II), viz. Cu⋯Cl = 3.153 (1) Å As shown in Fig. 4The crystal packing in compound (II)E)-1-[diazenyl]naphthalen-2-ol -1-(phenyldiazenyl)naphthalen-2-ol and its derivatives gave seven hits -1-(phenyldiazenyl)naphthalen-2-ol  and 9.2 (3)°. Among the other six complexes, in which the metal atoms are all located on inversion centres, there are three copper(II) complexes with the ligands (E)-1-(phenyldiazenyl)naphthalen-2-ol -1-(2-chlorophenyl)diazenyl]naphthalen-2-ol -1-diazenyl]naphthalen-2-ol -1-(phenyldiazenyl)naphthalen-2-ol -1-(3-methylphenyl)diazenyl]naphthalen-2-ol -1-(2-methylphenyl)diazenyl]naphthalen-2-ol  and 83.87 (6)°, respectively. In the other four complexes, the corresponding dihedral angles are 19.12 and 32.72 (12)° for the copper complexes CBANAP and AFATIM, respectively, and 24.06 (15) and ca 35.56° for the nickel complexes NOTNUH and TOAZNI, respectively.In the title ligand -1-[diazenyl]-naphthalen-2-ol (2.0 mmol) and M(OAc)2·H2O  was stirred at 298 K in a mixture of THF/MeOH (10/10 ml) for 24 h. The solvents were removed under vacuum and the residue was washed twice with hexane to give dark solids. The resulting solids were crystallized from CH2Cl2 to yield red block-like crystals for (I)The title compounds were synthesized by the following procedure: (Uiso(H) = 1.2Ueq(C). For the copper(II) complex (I)PLATON .Crystal data, data collection and structure refinement details are summarized in Table 710.1107/S205698901601080X/su5299sup1.cifCrystal structure: contains datablock(s) global, I, II, III. DOI: 10.1107/S205698901601080X/su5299Isup3.hklStructure factors: contains datablock(s) I. DOI: 10.1107/S205698901601080X/su5299IIsup4.hklStructure factors: contains datablock(s) II. DOI: 10.1107/S205698901601080X/su5299IIIsup2.hklStructure factors: contains datablock(s) III. DOI: 1490056, 1490055, 1490054CCDC references:  crystallographic information; 3D view; checkCIF reportAdditional supporting information:


The need of heat exchanger in the ECMO circuit is controversial. Moreover, how to monitor patient central temperature during extracorporeal support is still not clear, but potentially useful for the detection of “unexpressed” fever, eventually related to septic complications.We conducted two in vitro experiments to estimate ECMO heat dispersion and obtain clinical information regarding patient central temperature during extracorporeal support.Experiment A. We analyzed heat dispersion of an ECMO circuit (Maquet Rotaflow PLS System) at 36 combinations of blood flow (BF 1-3-5 L/min), gas flow (GF 0-5-10 L/min) and set temperature (T set 36-37-38-39 °C). in any condition, heat dispersion was considered equal to the power (Watts) generated by the heat exchanger at the steady state, defined as stable temperature throughout the circuit.Experiment B. By a reservoir bag, we connected two circuits (pump+oxygenator+heat exchanger), one simulating the patient and the other the ECMO circuit. Patient and ECMO circuit T set ranged 36-39 °C and 35-39 °C, respectively, for overall 63 conditions; ΔT was patient - ECMO circuit T set difference. the power generated by the two heat exchangers  was recorded at constant patient BF (5 L/min) and ECMO BF and GF (3 L/min each).A) Overall, BF was 3.0 ± 1.7 L/min, GF 5.0 ± 4.1 L/min, pump rate 1299 ± 615 rpm, T set 37.5 ± 1.1 °C and circuit heat dispersion 58 ± 12 W (range 37.5-90), corresponding to a supposed patient metabolic consumption of 1196 ± 246 Kcal/die (range 774-1857) in case of heat exchanger absence or inactivation. It was affected by GF and T (p < 0.001), but not by BF (p = 0.9)  For ΔT > 0 heat exchanger did not generate energy, while for ΔT < 0 it supplied energy proportional to ΔT (p < 0.001). For ΔT = 0, heat exchanger power was 49 ± 7 W (range 40-55) Figure .Figure 22R. T set on heat exchanger is well matched with patient central temperature when its power is in the 40-55 W range, whereas lower power values may be associated to patient “unexpressed” fever.ECMO heat dispersion depends on GF and temperature, but not on BF. Therefore, heat exchanger should be considered also during low BF/high GF ECCO


H-imidazol-3-ium hydrogen oxalate dihydrate, N—H⋯ and O—H⋯O hydrogen bonds link the components into a bilayer-like assembly.In the title molecular salt 2-methyl-1 4H7N2+·HC2O4−·2H2O, were isolated from the reaction of 2-methyl-1H-imidazole and oxalic acid in a 1:1 molar ratio in water. In the crystal, the cations and anions are positioned alternately along an infinite [010] ribbon and linked together through bifurcated N—H⋯ hydrogen bonds. The water molecules of crystallization link the chains into (10-1) bilayers, with the methyl groups of the cations organized in an isotactic manner.Single crystals of the title molecular salt, C In 2010, Callear and co-workers described various topologies based on imidazolium/dicarboxylic acid combinations and showed the crystal-packing effects of substitution in the imidazole ring H-imidazole and oxalic acid in a 1:1 molar ratio in water.Imidazolium-type building blocks are useful in the field of crystal engineering es Fig. 1. The hydes Fig. 1.b-axis direction. Considering the orientation of the methyl groups of the cations along the ribbon, the sequence can be described as ‘isotactic’. The cations and anions are positioned alternately and are almost coplanar [dihedral angle between adjacent species = 1.15 (9)°].Hydrogen-bonding interactions are listed in Table 1As well as the cation-to-anion links, the OH group of the anion acts as a hydrogen-bond donor with one molecule of water, which is also the donor for hydrogen-bond interactions with (i) a second molecule of water and (ii) an O atom of a hydrogen oxalate anion involved in a neighbouring ribbon. The second water molecule also bridges two distinct hydrogen oxalate anions through two O—H⋯O hydrogen bonds. Thus, all the O atoms of the hydrogen oxalate anions are involved in the hydrogen-bonding network.4H7N2+ and HC2O4− assembled in infinite ribbons; (ii) parallel ribbons of C4H7N2+/HC2O4− connected together by water molecules, which leads to a staircase–sheet structure; (iii) sheets stacked in pairs which can be described as a two-dimensional bilayer-like arrangement propagating in -(+)-2-[2-(biphenyl-2-yl)-1-methylethyl]-4,5-dihydro-1H-imidazolium hydrogen oxalate -(−)-6-(4-bromophenyl)-2,3,5,6-tetrahydrothiazoloimidazolium hydrogen oxalate  and H2C2O4·2H2O  in water (100 ml) were mixed together at room temperature (301 K). Needle-shaped colourless crystals of (I)Equimolar solutions of 2-methyl-1Uiso(H) = 1.2Ueq, or hydroxy O—H = 0.84 Å, water O—H = 0.85 Å and methyl C—H = 0.98 Å, and with Uiso(H) = 1.5Ueq.Crystal data, data collection and structure refinement details are summarized in Table 210.1107/S2056989016011038/hb7595sup1.cifCrystal structure: contains datablock(s) global, I. DOI: 10.1107/S2056989016011038/hb7595Isup2.hklStructure factors: contains datablock(s) I. DOI: Click here for additional data file.10.1107/S2056989016011038/hb7595Isup3.cmlSupporting information file. DOI: 1491387CCDC reference: crystallographic information; 3D view; checkCIF reportAdditional supporting information: