A novel synthesis of some 1,4‐phenylene‐bis‐heterocyclic carboxamide derivatives

N,N ′‐(1,4‐phenylene)bis(3‐oxo‐3‐phenylpropanamide) 1 reacts with DMFDMA in refluxing toluene to afford N,N ′‐(1,4‐phenylene)bis(2‐benzoyl‐3‐(dimethylamino)acrylamide) 2 . Compound 2 reacts with a twofold excess of the active methylene reagents 3a , 3b , 3c to afford the pent‐2‐enediamide derivatives 7 and 8a , 8b , respectively. Compounds 7 and 8a could be cyclized to afford the same compound N,N ′‐(1,4‐phenylene)bis(5‐cyano‐6‐oxo‐2‐phenyl‐1,6‐dihydropyridine‐3‐carboxamide) 9a while 8b was cyclized to afford the 6‐thioxo analogue 9b . Compound 2 reacts with hydrazine derivatives 10a , 10b in refluxing ethanol/piperidine to afford the hydrazinylacrylamide derivatives 11a , 11b , which have been cyclized to the corresponding N,N ′‐(1,4‐phenylene)bis(1 H ‐pyrazole‐4‐carboxamide) derivatives 12a , 12b , respectively. Compound 2 reacts also with urea derivatives 13a , 13b , 13c in refluxing ethanol/piperidine to afford the N,N ′‐(1,4‐phenylene)bis(2‐benzoyl‐3‐substituted‐acrylamide) derivatives 14a ‐ c , which could be cyclized into N,N ′‐(1,4‐phenylene)bis(6‐phenyl‐1,2‐dihydropyrimidine‐5‐carboxamide)‐2‐oxo; 2‐thioxo or 2‐imino derivatives 15a , 15b , 15c , respectively. J. Heterocyclic Chem., (2009).