Synthesis of Novel Series of Coumarin Derivatives

Khalid M Darwish; Hussniya A Al-difar; Al Khansaa El-hawat; M. G. Elarfi; T. M. Awin; Haneen Al- difar

Abstract

In a synthetic method similar to Knoevenagel reaction, 3-acetyl coumarin was prepared in the same way through a cyclization condensation reaction betweensalicylaldehyde and ethyl acetoacetate under basic condition using piperidine. Hence, 3-acetyl coumarin as a starting material was reacted with bromine in ether using a Lewis acid as a reactioncatalyst to produce the corresponding α–bromoaceyl cromen-2-one derivative. In application ofHantzsch synthesis, the reaction of α–bromoaceyl cromen-2-one with thioacetamide in ether afforded a3-methylthiazolyl cromen-2-one derivative also by a cyclization condensation reaction. On the otherhand, the α–bromoaceyl cromen-2-one was also reacted with potassium thiocyanide in ethanolaffording an α–cyanoaceyl cromen-2-one derivative. The latter was then reacted with phenyldiazoniumand 3-methoxyphenyldiazonium salts in sodium acetate solution affording their correspondinghydrazonyl derivatives as Schiffs’ bases. Purity of the synthesized compounds was checked with thinlayer chromatography techniques and melting point measurements before and after recrystallization. Allthe physical and spectral data of the synthesized compounds have been measured

Abstract

Keywords