Reactions of some pyranylidene esters with amines

The reactions of 4-(2,2-dimethyl-4,6-dioxo-1,3-dioxan-5-ylidene)-2,6-diphenyl-4H-pyran ( 1 ) with primary amines gave the corresponding 1-substituted 1,4-dihydropyridine derivatives. The related benzo derivative of 1 (12) and primary amines gave 3-substituted 3,4-dihydro-2-phenyl-5H-[1]benzopyrano[3,4-c] pyridine-4,5-dione derivatives. With secondary amines, 12 gave 2-phenyl-4H,5H-pyrano[3,4-c] [1]benzopyrane-4,5-dione, and with isopropylamine, N,N-dimethylhydra-zine, and methanolic potassium hydroxide, 12 gave 4-phenacylcoumarin. Some reaction intermediates were isolated which indicate probable reaction paths. The reactions with amines were extended to a naphtho derivative of 1 (19) and to a thia homolog of 12 (24).