Preparation of New 2-Amino- and 2,3-Diamino-pyridine Trifluoroacetyl Enamine Derivatives and Their Application to the Synthesis of Trifluoromethyl-containing 3H-Pyrido[2,3-b][1,4] diazepinols

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-ClC(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-3H-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.