Aryl a-acylaminoketones

These a-acylaminoketones also provided a convenient synthesis of thiazoles on treatment with phosphorus pentasulfide (Gabriel s method). Although yields range from 45 to 80%, substituents are usually restricted to alkyl, aryl and alkoxy derivatives. Thus, reaction of the a-acylaminoketone (4) with P4S1Q gave the thiazole (5), and thiazole (7) itself was prepared in this manner in 62% yield from formylaminoacetal (6) (14CB3163). The corresponding 5-ethoxy compound was obtained from the a-formamidoester and phosphorus pentasulfide in an inert solvent. 

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