反应详情

3-(2-Amino-thiazol-5-yl)-2-benzhydryloxycarbonyl-7-t-butoxycarbonylamino-8-oxo-5-thia-1-azabicyclo[4.2.0]-oct-2-ene (1.13 g) is treated in accordance with the working method described in Example 1 (B), the acetyl chloride being replaced by methyl chloroformate (0.19 cc). The crude product obtained is chromatographed on a column (height: 30 cm, diameter: 3 cm) of silica gel (0.04-0.06 mm), elution being carried out under a pressure of 0.4 bar (40 kPa) with a 40:60 (by volume) mixture of cyclohexane and ethyl acetate; 50 cc fractions are collected and are analysed by chromatography on a thin layer of silica gel (eluant: a 40:60 (by volume) mixture of cyclohexane and ethyl acetate). The fractions containing the pure expected product (Rf=0.3) are combined and concentrated to dryness under reduced pressure (30 mm Hg; 4 kPa) at 30° C. 2-Benzhydryloxycarbonyl-7-t-butoxycarbonylamino-3-(2-methoxycarbonylamino-thiazol-5-yl)-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene (0.73 g) is obtained in the form of a yellow froth.

1. customThe crude product obtained
2. customis chromatographed on a column (height: 30 cm, diameter: 3 cm) of silica gel (0.04-0.06 mm), elution
3. additionbeing carried out under a pressure of 0.4 bar (40 kPa) with a 40:60 (by volume) mixture of cyclohexane and ethyl acetate
4. custom50 cc fractions are collected
5. additiona 40:60 (by volume) mixture of cyclohexane and ethyl acetate)
6. additionThe fractions containing the pure expected product (Rf=0.3)
7. concentrationconcentrated to dryness under reduced pressure (30 mm Hg; 4 kPa) at 30° C