Cephems cefixime

C2,H2oCl2N20,S 107837-26-3) see t/.t-Cefprozil diphenylmethyl 7-amino-3-chloromethyl-3-cephem-4-carboxylate monohydrochloride (C2,H2oCl2N20,S 79349-53-4) see Cefixime diphenylmethyl 7-amino-7-methoxycephalosporanatc (C24H24N20 S 35565-04-9) see Cefoxitin diphenylmethyl 7(R)-7-amino-7-methoxy-3-(l-methyl-tetrazol-5-ylthiomethyl)-l-oxa-l-dethia-3-cephem-4-carb-oxylate... 

C22H21CIN2O3S 79349-67-0) see Cefixime diphenylmethyl 7(S)-azido-7-bromocephalosporanate (C23HiijBrN405S 35565-02-7) see Cefoxitin diphenylmethyl 7(S)-azido-7-methoxycephalosporanate (C24H22N4O6S 35565-03-8) see Cefoxitin diphenylmethyl 7a-benzamido-3-chloromethyl-l-oxa-3-cephem-4 -carboxy late... 

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). 

The determination of cephalexin, cefixime, ceftriaxone, cefotaxime based on the Bent-French method, in which degradation products of P-lactam analogs with metal ions form the colored complexes, was developed. Hydroxamic acids formed by hydroxiaminolysis of cephem analogs (1 3), formed complexes with iron (II) ions (Fig. 13) [44]. 

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