The synthesis of a novel series of analogous intermediates N3‐[1‐alkyl(aryl/heteroaryl)‐3‐oxo‐4,4,4‐trichloroalk‐1‐en‐1‐yl]‐2,3‐diaminopyridines and N2‐(methanesulfonyl) [Cl3CC(O)CHCRNH(C5H3N)NHY], where R = H, Me, C6H5, 4‐FC6H4, 4‐ClC6H4, 4‐BrC6H4, 4‐CH3C6H4, 4‐OCH3C6H4, 4,4′‐biphenyl, 1‐naphthyl, 2‐thienyl, 2‐furyl, and Y = H, SO2Me, is reported. A new corresponding series of 2‐aryl/heteroaryl‐3H‐pyrido[2,3‐b][1,4]diazepin‐4(5H)‐ones obtained from intramolecular cyclization reaction of the first series of trichloroacetyl enamines or from the direct cyclocondensation reaction of 4‐methoxy‐1,1,1‐trichloalk‐3‐en‐2‐ones with 2,3‐diaminopyridine, under mild conditions, is also demonstrated. J. Heterocyclic Chem., (2009).