Patent ID: 7705154

Claim:
A process for the preparation of 2-substituted-5-(1-alkylthio)alkylpyridine (I), wherein R 1 and R 2 independently represent H, or C 1 -C 4 alkyl; and R 3 represents C 1 -C 4 alkyl; and R 4 represents C 1 -C 4 alkyl or C 1 -C 4 haloalkyl; which comprises: a) condensing a substituted enone (II) wherein R 4 is as previously defined; and R 5 represents C 1 -C 4 alkyl; with an enamine (III) wherein R 1 and R 2 are as previously defined; and R 6 and R 7 independently represent C 1 -C 4 alkyl or R 6 and R 7 taken together with N represent a 5-membered saturated ring; and cyclizing in the presence of ammonia or a reagent capable of generating ammonia to produce a 2,5-disubstituted pyridine (IV) wherein R 1 , R 2 and R 4 are as previously defined; b) chlorinating or brominating the 2,5-disubstituted pyridine (IV) to provide a haloalkylpyridine (V) wherein R 1 , R 2 and R 4 are as previously defined; and X represents Cl or Br; and c) treating the haloalkylpyridine (V) with mercaptan salt (VI) R 3 S − M + (VI) wherein R 3 as previously defined; and M represents an alkali metal to give 2-substituted-5-(1-alkylthio)alkylpyridine (I).