Diol epoxides conformational-reactivity

This procarcinogen undergoes metabolic conversion to benzo[a]pyrene diol epoxides, BPDEs (5,28-31), which have been the focus of structural and conformational studies by theoretical and experimental methods. These chemically reactive BPDEs are involved in covalent binding to DNA (13-22). 

The novel bay-region diol epoxide isomers (93) have proved to be remarkably biologically active, despite their relative lack of reactivity towards hydrolysis (as expected from simple PMO calculations). Both diastereo-isomers prefer the conformation in which the OH groups are quasi-diequatorial, and these are the most tumorigenic diol epoxides yet tested on mouse skin. 

Epoxide, Diol,and Double Bond Reactivity.—Berti and co-workershave examined the reactivity of the conformationally rigid epoxides (134) and (135) with HCl. The two epoxides react in dry CHCI3 to yield almost exclusively (136) and (137), the products of syn-attack by chloride ion on the benzylic carbon. However, with HCl in propan-2-ol, (134) gives (136), (22%) and (138) (78%),... 

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