Synthesis of 5-alkyl-4-amino-2-(trifluoromethyl)pyridines and their transformation into trifluoromethylated 1H-pyrazolo[4,3-c]pyridines

5-Alkyl-4-amino-2-(trifluoromethyl)pyridines were prepared in good yields starting from the corresponding pyridinols either using condensation with tosyl isocyanate or by alkylation with 2-chloroacetamide and subsequent Smiles type rearrangement. The cyclisation of diazonium salts, generated from 5-alkyl-4-amino-2-(trifluoromethyl)pyridines afforded trifluoromethylated 1H-pyrazolo[4,3-c] pyri dines. (C) 2001 Elsevier Science Ltd. All rights reserved.