Crystal and mol-ecular structure of aflatrem.
The crystal structure of the title compound, C32H39NO4, confirms the absolute configuration of the seven chiral centres in the mol-ecule. The molecule has a 1,1-dimethylprop-2-enyl substituent on the indole nucleus and this nucleus shares one edge with the five-membered ring which is, in turn, connected to a sequence of three edge-shared fused rings. The skeleton is completed by the 7,7-trimethyl-6,8-dioxabi-cyclo-[3.2.1]oct-3-en-2-one group connected to the terminal cyclohexene ring. The two cyclohexane rings adopt chair and half-chair conformations, while in the dioxabi-cyclo-[3.2.1]oct-3-en-2-one unit, the six-membered ring has a half-chair conformation. The indole system of the mol-ecule exhibits a tilt of 2.02 (1)° between its two rings. In the crystal, O-H⋯O hydrogen bonds connect mol-ecules into chains along [010]. Weak N-H⋯π inter-actions connect these chains, forming sheets parallel to (10-1).
['Lenta|Bruno N|BN|', 'Ngatchou|Jules|J|', 'Kenfack|Patrice T|PT|', 'Neumann|Beate|B|', 'Stammler|Hans-Georg|HG|', 'Sewald|Norbert|N|']
aflatrem crystal structure hydrogen bonding Aspergillus species N—H⋯Cg (indole) fungal endophytes indole-diterpenoid