Nucleophilic displacement in 2-chloro(trifluoromethyl)pyridines with amines and ammonia

The activating effect of trifluoromethyl groups in 2-chloro(trifluoromethyl)pyridines was investigated by comparing reactions of these compounds and of 2-chloropyridine with secondary cyclic amines. The ammonolysis of 2-chloro-3-trifluoromethylpyridine and 2-chloro-4-trifluoromethylpyridine is also reported and shown to proceed, in contrast to the reported behaviour of 2-chloro-5-trifluoromethylpyridine, without hydrolysis of the trifluoromethyl function. Both 2-amino-3-trifluoromethylpyridine and 2-amino-4-trifluoromethylpyridine were converted (via the corresponding pyridones) to 3-trifluoromethylpyridin-2(1H)-thione and 4-trifluoromethylpyridin-2(1H)-thione, and a number of S-alkyl derivatives of the latter compounds were prepared. (C) 1999 Elsevier Science S.A. All rights reserved.