DEOXYDATIVE SUBSTITUTION OF PYRIDINE 1-OXIDES BY THIOLS .20. REACTIONS OF (2, 3, AND 4-PHENYL)PYRIDINE, 3-ACETAMIDOPYRIDINE, 3-BROMOPYRIDINE, 3-ACETOXYPYRIDINE, 3-ETHOXYPYRIDINE 1-OXIDES WITH 1-ADAMANTANETHIOL IN ACETIC-ANHYDRIDE

Substitutions of 2, 3, and 4-substituted pyridine 1-oxides by 1-adamantanethiol in acetic anhydride takes place at available alpha-, to a lesser degree at beta-, and rarely at gamma-ring carbons. It was found that 2-phenylpyridine I-oxide produces a mixture of 5- and 6-(1-adamantylthio)-2-phenylpyridines, and 4-phenylpyridine 1-oxide a mixture of 2- and 3-isomeric sulfides. Substitutions of the 1-oxides of 3-phenyl-, 3-acetamido-, 3-acetoxy-, 3-bromo-, and 3-ethoxypyridine by 1-adamantanethiol in acetic anhydride led to mixtures consisting predominantly of 2- and 6-sulfide, and to a lesser extent, the 5-sulfide. When triethylamine is present in other. wise identical reaction mixtures, the ratio of alpha to beta-sulfides increases. From the reactions of 3- and 4-phenylpyridine 1-oxides, there were isolated some N-acetyl hydroxy (or acetoxy) 1-adamantylthio substituted 1,2,3,4-and 1,2,3,6-tetrahydropyridines, whose structures are discussed.