A one-pot reaction of (chlorocarbonyl) phenyl ketene with β-ketoamides and thiochromen-2-one

Abstract

Readily available (chlorocarbonyl)phenyl ketene and a varied set of β-ketoamides were reacted in a one-step procedure to produce 2-pyrone derivatives. β-Ketoamide derivatives are versatile intermediates for the synthesis of heterocyclic compounds. For instance, 1-morpholino-3-phenyl-1,3-propanedione, 1-phenyl-3-piperidino-1,3-propanedione, 1-phenyl-3-pyrrolidino-1,3-propanedione, 1-piperidino-1,3-butanedione, 1-morpholino-2-phenyl ethanone were used in these reactions to produce 2-pyrone derivatives. In addition, the preparation of 4-hydroxy-3-phenylthiochromeno[4,3-b]pyran-2,5-dione derivatives and 4-hydroxy-7-methyl-3-phenyl pyrano[3,2-c]chromeno-2,5-dione were described. For the synthesis of these compounds 4-hydroxy-2H-thiochromen-2-ones and 4-hydroxy-8-methyl-2H-chromen-2-one were reacted with (chlorocarbonyl)phenyl ketene and the final products were isolated in good yields.