p-Nitrobenzyl alpha-[4-mercapto-3-phenoxyacetamido-2-oxoazetidin-1-yl]-alpha-(2-bromo-1-hydroxyethylidene)acetate → p-Nitrobenzyl 3-hyroxy-7-phenoxyacetamido-3-cephem-4-carboxylate

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Reaction Steps

To a solution of p-nitrobenzyl α-[4-mercapto-3-phenoxyacetamido-2-oxoazetidin-1-yl]-α-(2-bromo-1-hydroxyethylidene)acetate (106 mg) in benzene (5 ml) is added silica gel F-254 (500 mg) distributed by E. Merck Ag., and the mixture is shaken at room temperature for 1 hour. The insoluble material is removed by filtration, and washed several times with chloroform. The filtrate and washed solution are combined and evaporated under reduced pressure to give p-nitrobenzyl 3-hydroxy-7-phenoxyacetamido-3-cephem-4-carboxylate (60 mg). Yield: 66.3%. m.p. 95.5°-99.5° C. IR: νmaxCHCl3 3400, 1785, 1685, 1605. NMR: δCDCl3 2.03s2H, 4.60s2H, 5.07+5.37ABq(4)2H, 5.37d(4)1H, 5.68dd(9;4)1H, 6.83-8.32m9H.

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