Reaction of 4-ethoxy-2-(2,3,3-trichloro-1-nitro-2-propenylidene)benzazetine with methyl- and phenyllithium

The reactions of 4-ethoxy-2-(2,3,3-trichloro-1-nitro-2-propenylidene)benzaz etine with methyl- and phenyllithium at a ratio of 1:2 result in replacemen t of one chlorine atom and formation, respectively, of 4-ethoxy-2-(2,3-dich loro-3-methyl-1-nitro-2-propenylidene)benzazetine and 4-ethoxy-2-(2,3-dichl oro-1-nitro3-phenyl-2-propenylidene)benzazetine in 45 and 52% yield. With e xcess phenyllithium (reactant ratio 1:5), a mixture of products is formed d ue to replacement of one, two, and three chlorine atoms by phenyl groups. A n analogous reaction with methyllithium is nonselective.