反应详情

To a solution of (Z)-2-(2-t-butoxycarbonylaminothiazol-4-yl)-2-hydroxyiminoacetic acid (86.3 g: 0.30 Mol.) in dimethylformamide (600 ml) are added potassium carbonate (92 g: 0.67 Mol.) and triphenylmethyl chloride (100 g: 0.36 Mol.), and the mixture is stirred at room temperature for 3 days. The reaction mixture is poured into a mixture of concentrated hydrochloric acid (111 ml) and ice water (1500 ml) and extracted with ethyl acetate. The extract is washed with water, aqueous 5% sodium hydrogen carbonate, 2% hydrochloric acid and brine, dried over sodium sulfate, and concentrated. The residue is crystallized from dichloromethane to give (Z)-2-(2-t-butoxycarbonylaminothiazol-4-yl)-2-trityloxyiminoacetic acid (144 g) as colorless crystals. Yield: 91%. mp. 157° to 158° C.

1. extractionextracted with ethyl acetate
2. washThe extract is washed with water, aqueous 5% sodium hydrogen carbonate, 2% hydrochloric acid and brine
3. dry with materialdried over sodium sulfate
4. concentrationconcentrated
5. customThe residue is crystallized from dichloromethane