Silverman B D, Lowe J P
Cancer Biochem Biophys. 1984 Sep;7(3):203-12.
Delocalization energies have been calculated for carbocations formed from several epoxide intermediates of the cyclopenta-fused isomers of benz[a]anthracene. Except for the epoxides of benz[l]aceanthrylene, the largest calculated delocalization energies associated with the other benzaceanthrylenes result from ring-opening of the epoxide on the cyclopenta-ring yielding an alpha' type carbocation. Benz[l]aceanthrylene exhibits special behavior resulting from steric crowding in the bay-region of the molecule. For this molecule the calculated ease of epoxide ring opening is essentially the same for the bay-region epoxide and for the epoxide on the five-membered ring. Relative values of delocalization energy should provide an important index for ranking the reactivity of metabolites of the benzaceanthrylenes and benzacephenanthrylene that are potentially involved in the initiation of mutagenesis/carcinogenesis.
已计算了由苯并[a]蒽的环戊稠合异构体的几种环氧化物中间体形成的碳正离子的离域能。除了苯并[l]ace蒽的环氧化物外，与其他苯并ace蒽相关的最大计算离域能是由环戊环上的环氧化物开环产生α'型碳正离子所致。苯并[l]ace蒽表现出特殊行为，这是由于分子的湾区存在空间拥挤。对于该分子，计算得出的湾区环氧化物和五元环上的环氧化物的环氧化物开环难易程度基本相同。离域能的相对值应为对可能参与诱变/致癌起始过程的苯并ace蒽和苯并ace菲的代谢物的反应性进行排名提供重要指标。
