Polyhalogenoaromatic compounds. Part VIII. Reaction of aryl-lithium compounds with tetrachloro-4-methoxypyridine, and of aryl-substituted polychloropyridines with n-butyl-lithium

Abstract

The reaction of phenyl-lithium with tetrachloro-4-methoxypyridine gave, successively, tetrachloro-4-phenylpyridine, trichloro-4,6-diphenylpyridine, and dichloro-2,4,6-triphenylpyridine; under mild conditions, p-methoxyphenyl-lithium, p-dimethylaminophenyl-lithium, and p-trifluoromethylphenyl-lithium gave the corresponding 4-aryltetrachloropyridines. With n-butyl-lithium, the 4-aryl-tetrachloropyridines gave the corresponding 4-aryltrichloro-3-pyridyl-lithium compounds. Attempts to trap 2-pyridynes generated by elimination of lithium chloride from the 3-pyridyl-lithium compounds were largely unsuccessful; with furan, the main products were the 4-aryl-2,3,6-trichloropyridines, but with trichloro-4-phenyl-3-pyridyl-lithium, a small amount of 2,3-dichloro-5,8-epoxy-5,8-dihydro-4-phenylquinoline was obtained.