7-Amino-3-vinyl-3-cephem-4-carboxylic

C23H22N2O3S 106447-41-0) see ci.t-Cefprozil diphenylmethyl 7-amino-3-vinyl-3-cephem-4-carboxylate hydrochloride... 

To a suspension of 7-amino-3-vinyl-3-cephem-4-carboxylic acid (11.25 g), 2-(aminothiazol-4-yl)-2-(tert-butoxycarbonylmethoxyimino)acetic acid S-mercaptobenzothiazole ester (23.88 g) in ethylacetate (266 ml) and water (9 ml) at 2°C is added triethylamine. After completion of the reaction, water is added and pH is adjusted to 2.1 with diluted sulfuric acid. The phases are separated and the aqueous phase is extracted with ethylacetate. The organic extracts are combined and concentrated to a volume of 120 ml, then acetonitrile (100 ml) and formic acid (22 ml) are added. The mixture is stirred at 30-35°C for 1 hour. The mixture is cooled to 2°C, the precipitate is filtered, washed with acetonitrile and dried to obtain 20.86 g of 5-thia-l-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid, 7-(((2Z)-(2-amino-4-thiazolyl)(carboxymethoxy)imino)acetylamino)-3-ethenyl-8-oxo-, (6R,7R)-(Cefixime). 

Amino-3-[(Z)-2-(methyl-5-thiazolyl)vinyl]-3-cephem-4-carboxylic acid Triethylamine... 

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