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‐4 H ‐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‐5 H ‐[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).