Trifluoromethyl-substituted 1,6-naphthyridines and pyrido[4,3-d]pyrimidines

A convenient method for the synthesis of 1-alkyl-5-trifluoromethyl-1,6-naphthyridin-4(1H)-ones was elaborated based on the reaction of 4-alkylamino-3-trifluoroacetimidoyl-3-penten-2-one diphenylboron chelates with dimethylformamide dimethyl acetal. 3-Acetyl-4-amino-2-trifluoromethylpyridine was used to obtain 5-trifluoromethyl-1,6-naphthyridin-4(1H)-one and its 2-methoxycarbonyl derivative, as well as 4-methyl-5-trifluoromethylpyrido-[4,3-d]pyrimidine.