X-ray crystallographic analysis of (+/-)-7 beta,8 alpha-dihydroxy-9 beta,10 beta-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene: molecular structure of a 'syn' diol epoxide.

X-ray crystallographic analysis has been used to define the molecular structure of the cis (syn) diol epoxide, (+/-)-7 beta,8 alpha-dihydroxy-9 beta, 10 beta-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene. The two hydroxyl groups are oriented equatorially to the tetrahydrobenzene ring, contrary to predictions and there is no intramolecular hydrogen bonding in the structure.