Preparation of new 2‐amino‐ and 2,3‐diamino‐pyridine trifluoroacetyl enamine derivatives and their application to the synthesis of trifluoromethyl‐containing 3<i>H</i>‐pyrido[2,3‐<i>b</i>][1,4] diazepinols

Abstract

Abstract magnified image The synthesis of a novel series of the intermediates N 2 ( N 3 )‐[1‐alkyl(aryl/heteroaryl)‐3‐oxo‐4,4,4‐trifluoroalk‐1‐en‐1‐yl]‐2‐aminopyridines [F 3 CC(O)CHCR 1 (2NHC 5 H 3 N)] and 2,3‐diaminopyridines [F 3 CC(O)CHCR 1 (2‐NH 2 ‐3‐NHC 5 H 3 N)], where R 1 = H, Me, C 6 H 5 , 4‐FC 6 H 4 , 4‐CIC 6 H 4 , 4‐BrC 6 H 4 , 4‐CH 3 C 6 H 4 , 4‐OCH 3 C 6 H 4 , 4,4′‐biphenyl, 1‐naphthyl, 2‐thienyl, 2‐furyl, is reported. The corresponding series of 2‐aryl(heteroaryl)‐4‐trifluoromethyl‐3 H ‐pyrido[2,3‐ b ][1,4]diazepin‐4‐ols obtained from intramolecular cyclization reaction of the respective trifluoroacetyl enamines or from the direct cyclocondensation reaction of 4‐methoxy‐1,1,1‐trifluoroalk‐3‐en‐2‐ones with 2,3‐diaminopyridine, under mild conditions, is also reported.