5-Thiazolyl-acetate, preparation

The Curtius rearrangement in acetic anhydride of the azide (8) prepared from 4-carboxythiazole yields 4-acetamidothiazole (Scheme 8) (47). The same reaction starting with ethyl-2-methyl-4-thiazolyl carboxy-late, failed to give the 4-aminothiazole (48). Heterocyclizations are more convenient synthetic methods (Chapter II. Table 40). 

The preparation and spectroscopic properties (infrared, ultraviolet, NMR) of iV-alkoxycarbonyl-N -(2-thiazolyl)thioureas (268) have been studied by the Nagano group (78, 264). These compounds react with bromine in acetic acid or chloroform to give 2--alkoxycarbonylimino-thiazolo[3,2-h]thiadiazolines (Scheme 162), whose structures were established by mass spectroscopy, infrared, NMR, and reactivity patterns (481). 

Famotidine, Also known as Pepcid, famotidine [76824-35-6] (AT-(aminosulfonyl)-3-([[2-[(diaminomethylene) amino]-4-thiazolyl] methyl]thio)propanimidamide (2) is a white to pale yellow crystalline compound, freely soluble in glacial acetic acid, slighdy soluble in methanol, very slightly soluble in water, and practically insoluble in ethanol. It may be prepared by the method described in Reference 3. 

Furium. N[4-(5-Nitro-2-furanyl)-2-thiazolyl]acetamide, has demonstrated activity against bacilli and pathogenic enterobacteria (24). The product, prepared from thiourea and 2-bromo-l-(5-nitro-2-furanyl)ethanone followed by acetylation of the intermediate arninothiazole with acetic anhydride in pyridine (25), is marketed in several countries for both human and veterinary use. 

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