Gabriel Synthesis of Thiazoles

Warming an acylamino ketone with a stoichiometric amount phosphorus pentasulfide yields the corresponding thiazole product. The reaction was first discovered by Gabriel in 1910.  

Several examples of this widely practiced name reaction have been applied in drug discovery abound. For example in a study describing the design and synthesis of inhibitors of hepatitis C virus (HCV) NS5B polymerase, thiazole intermediate was constructed via the Gabriel reaction,  

Similarly, Boyd and co-workers at the R. W. Johnson Pharmaceutical Research Institute used this reaction for the synthesis of several imidazolyl thiazole derivatives to study significant R2A/D adrenoceptor binding affinity and in vivo anti-nociceptive activity in mice as part of a program to develop analgesic agents. 

A variant of this transformation has been reported with Lawesson s reagent. Kiryanov et al. during their studies on cyclization of 1,4-dicarbonyl compounds mediated by Lawesson s reagent, found that 2-alkoxy-l,3-thiazole could be synthesized readily using a conventional microwave oven 

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