Synthesis of Substituted Quinones. 2,5-Disubstituted 1,4-Benzoquinones

Article abstract of DOI:10.1021/jo01313a009

Synthetic methodology is presented which allows the facile synthesis of 2,5-disubstituted 1,4-benzoquinones.This involves the initial 1,2-addition of an alkynyllithium reagent to one of the carbonyl groups of 2,5-diethoxy- or 2,5-dichloro-3,6-dimethoxy-1,4-benzoquinone.This is followed by an analogous addition of an alkyl-, aryl-, or alkynyllithium to the remaining carbonyl to give a cyclohexa-2,5-diene-1,4-diol derivative.Acid hydrolysis of these adducts results in the 2,5-dialkylated 1,4-benzoquinones.This methodology was employed to prepare 7-chloro-6-methyl-1,2,5,8-tetrahydro-3H-pyrrolo<1,2-α>indole-5,8-dione (14), a compound having the basic ring systeme of the mitomycin antineoplastic antibiotics.