反应详情

1.59 g (4 mmols) of diphenylmethyl 7β-amino-3-chloro-3-cephem-4-carboxylate are dissolved in 5 ml of trifluoroacetic acid at 0° and the solution is stirred for 15 minutes. The clear, pale yellow solution is diluted with 20 ml of toluene and then freed from excess trifluoroacetic acid and toluene under reduced pressure. The residue is dissolved in about 20 ml of water/ethyl acetate (1:1), the organic phase is separated off and the acid aqueous phase is brought to a pH of 3.0 with 20% strength triethylamine in methanol. The pale yellow precipitate is filtered off, washed with ethyl acetate and diethyl ether and dried under a high vacuum. 320 mg of 7β-amino-3-chloro-3-cephem-4-carboxylic acid are isolated as a pale yellow amorphous powder; thin layer chromatogram: Rf = 0.08 (silica gel, n-butanol/acetic acid/water, 67:10:23).

1. customthe organic phase is separated off
2. filtrationThe pale yellow precipitate is filtered off
3. washwashed with ethyl acetate and diethyl ether
4. customdried under a high vacuum