反应详情

To a solution of benzyl 7β-amino-3-methyl-3-cephem-4-carboxylate (1.2 g) and anisole (5.2 ml) in methylene chloride (100 ml) is added a solution of titanium tetrachloride (2.6 g) in nitromethane under ice cooling, and the mixture stirred for 9.5 hours at room temperature. The reaction mixture is adjusted to pH 1 or less with diluted hydrochloric acid (70 ml), washed with ethyl acetate, and neutralized with 6 N-sodium hydroxide. The resulting titanium hydroxide is removed by filtration, and the filtrate concentrated under reduced pressure at a temperature below 50° C. The resulting crystals are collected by filtration to give 7β-amino-3-methyl-3-cephem-4-carboxylic acid (270 mg). Yield: 32%. This product was identical with an authentic specimen in NMR and IR spectra.

1. washwashed with ethyl acetate
2. customThe resulting titanium hydroxide is removed by filtration
3. concentrationthe filtrate concentrated under reduced pressure at a temperature below 50° C
4. filtrationThe resulting crystals are collected by filtration