Aromatic substitution. Part XXV. Reaction of 3-picoline with some substituted phenyl-lithium derivatives

Abstract

A study of the reactions of o-tolyl-, o-ethylphenyl-, and p-methoxyphenyl-lithium with 3-picoline has shown that the substituent has little effect upon the ratio of the 2,3- and 2,5-isomers formed. o-Tolyl-lithium gave, in addition, some 3-methyl-5-o-tolylpyridine, and 3-methyl-1,2,5,6-tetrahydro-2-o-tolylpyridine could be isolated under certain conditions. The latter arises by disproportionation of the intermediate σ-complex while the former probably results from the attack of this σ-complex by o-tolyl-lithium. An attempt to reduce 3-methyl-2-o-tolylpyridine to the tetrahydro-derivative with lithium aluminium hydride and aluminium chloride was unsuccessful.