Reaction of 2-Imino-2,5-dihydrofuran-3-carboxamides with Benzaldehyde

The reaction of 2-imino-2,5-dihydrofuran-3-carboxamides with benzaldehyde in pentan-1-ol in the presence of piperidine gave new dihydrofuran derivatives with a fused pyrimidine ring and two phenyl rings, 2-phenyl-5-(2-phenylethylidene)-5,6-dihydrofuro[2,3-d]pyrimidin-4(3H)-ones. The product structure was confirmed by spectroscopic methods (1H and 13C NMR) and independent synthesis from previously reported 2-imino-5,5-dimethyl-4-(2-phenylethenyl)-2,5-dihydrofuran-3-carboxamide and benzaldehyde under similar conditions.