To a cooled (5° C.), stirred solution of 0.328 g. of benzhydryl 7-(2-thienylacetamido)-3-(1-acetoxyethyl)-3-cephem-4-carboxylate in 1 ml. of anisole was added 1 ml. of cold trifluoroacetic acid. The reaction mixture was allowed to stir with cooling for 20 minutes after which time was added 30 ml. of n-heptane. The reaction mixture was evaporated in vacuo to a low volume, 20 ml. of n-heptane was added, and the resulting mixture was stirred with cooling for five minutes. The solid obtained by filtration of the resulting solution was dissolved in acetone, and the acetone solution was then filtered and evaporated to near dryness. The residue was dissolved in ethyl acetate, and the resulting solution was extracted three times with cold aqueous sodium bicarbonate solution. The aqueous extracts were combined, layered with ethyl acetate, and acidified with 1N.HCl. The organic layer was separated, washed with brine, and dried over anhydrous sodium sulfate. Evaporation in vacuo to dryness gave 94 mg. (40.5 percent) of the title product:
