New synthesis of 2-trifluoromethyl-2,3-dihydro-1H-quinolin-4-ones

N-(1-Ethoxy-2,2,2-trifluoroethyl)anilines 2a–2f, prepared from trifluoroacetaldehyde ethyl hemiacetal and aniline, readily reacted with diethyl malonate in the presence of sodium hydride, giving substituted products 5a–5f in high yields. Compounds 5a–5f subjected to hydrolysis and decarboxylation under specified conditions yielded the 4,4,4-trifluorobutyric acids 6a–6e or 7. Direct ring-closure of 6a–6e with polyphosphoric acid gave 2-trifluoromethyl-2,3-dihydro-1H-quinolin-4-ones 9a–9e.