2- thiazoles, syntheses 4,5-disubstituted derivatives

Aiiiino-4-phenylthiazoles, from o-diazo-acetophenone and thiourea, 231 2-Amino-5-phenylthiazole, diuretic prope ties of Schiffs bases of, 167 synthesis of, by condensation of ammonia with At(ary 1-1,3-oxathiol-2-yIidine) tertiary iminium salts. 300 2-(p-Ammophenyl) thiazoles, syntheses of, 4,5-disubstituted derivatives of, 191 2-Amino5-substituted thiazoles, from o-haloaiddiydes and thiourea, 224, 225 /V,At -bis (2-Amino-4 substituted thiazolyl)-p biphenylene, from p-biphenylene dithiourea and o-halocarbonyl compounds, 243... 

An interesting new synthesis of 2,4,5-trisubstituted and 2,4-disubstituted alkylthiazoles has been reported by Dubs (807). Heating the easily obtainable derivatives (276) with ammonium acetate in acetic acid gives thiazoles (10), Rj, Rj = alkyl and R3 = H or alkyl in good yields (Scheme 143). 

The synthesis of N, /V-disubstituted 2-amino-5-acylthiazoles has been reported. Starting from the thiourea 71 reaction with a-halomethyl ketones 72 furnished the thiazoles 73 in good yields. This method is useful for preparing AfN-bisaryl derivatives <02T2137>. 

This type of approach constitutes a convenient synthesis of 5-functionalized thiazoles. 2,4-Diamino-S-acylthiazoles (292) can be prepared by reacting a-haloketones with alkyl- or aryl-3-amidinothioureas (290) in the presence of triethylamine <86S353> with iV-(anilino)benzylidenc-JV,iV -disubstituted thioiurcas (291), the reaction affords 2-amino-4-aryl-5-acyltWazoles (293). In contrast, the corresponding iV-benzoylthioureas (294) afford mainly 5-benzoyl derivatives (295)... 

Rajan S, Hardik G, Thaker M, Tony G, Kamala K. V. Design, synthesis and characterization of novel 2-(2,4-disubstituted-thiazole-5-yl)-3-aryl-3H-quinazoline-4-one derivatives as inhibitors of NF-kB and AP-1 mediated transcription activation and as potential anti-inflammatory agents, Eur. J. Med. Chem. 2009. p. 2184 - 2189. DOI 10.1016/i.ejmech.2008.10.031... 

Kumar Y, Green R, Borysko K. Z, Wise D. S, Wotring L. L, Townsend L. B. Synthesis of 2,4-disubstituted thiazoles and selenazoles as potential antitumor and antifilarial agents. 1. Methyl 4-(isothiocyanatomethyl)thiazole-2-carbamates, -selenazole-2-car-bamates, and related derivatives, J. Med. Chem. 1993. p. 3843 - 3848. DOI 10.1021/ jm00076a012... 

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