Diazomethane → Diphenylmethyl (6R-trans)-3-methoxy-8-oxo-7-(phenoxyacetamido)-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylate

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Reaction Steps

The resulting 7β-phenoxyacetamido-3-hydroxy-3-cephem-4-carboxylic acid diphenylmethyl ester is taken up in methanol and treated, at 0° C., with an excess of an ethereal solution of diazomethane. After a reaction time of 5 minutes, the solution is concentrated completely and the oily residue is chromatographed on silica gel thick layer plates (toluene/ethyl acetate, 3:1). The silica gel in the zone at Rf=0.19 is extracted with ethyl acetate and gives 7β-phenoxyacetamido-3-methoxy-ceph-3-em-4-carboxylic acid diphenylmethyl ester; melting point 120° C. (from ether), IR spectrum (in CHCl3); 3310, 1775, 1700, 1690 and 1600 cm-1.

Provenance & Evidence