反应详情

A mixture of 2-benzhydryloxycarbonyl-7-[2-methoxyimino-2-(tritylamino-thiazol-4-yl)-acetamido]-8-oxo-3-(2-tosyloxy-vinyl)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene (syn isomer, E-form) (0.494 g), acetone (20 cc) and p-toluenesulphonic acid hydrate (10 mg) is heated under reflux for 20 hours. It is then concentrated to dryness under 20 mm Hg at 20° C., the residue is taken up in ethyl acetate (30 cc) and a 5% strength sodium bicarbonate solution (20 cc), and the organic phase is decanted, dried over sodium sulphate, filtered and concentrated to dryness under 20 mm Hg at 20° C. The residue is chromatographed on a column (column diameter: 3 cm, height: 27 cm) of Merck silica gel (0.06-0.2 mm) (50 g). Elution is carried out with ethyl acetate (0.4 liter), 20 cc fractions being collected. Fractions 8 to 10 are a mixture of the starting material and of the expected product; fractions 11 to 17 are concentrated to dryness under 20 mm Hg at 20° C. 7-[2-(2-amino-thiazol-4-yl)-2-methoxyimino-acetamido]-2-benzhydryloxycarbonyl-8-oxo-3-(2-tosyloxy-vinyl)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene (syn isomer, E-form) (0.15 g) is obtained in the form of a cream-coloured solid.

1. temperatureis heated
2. temperatureunder reflux for 20 hours
3. concentrationIt is then concentrated to dryness under 20 mm Hg at 20° C.
4. customa 5% strength sodium bicarbonate solution (20 cc), and the organic phase is decanted
5. dry with materialdried over sodium sulphate
6. filtrationfiltered
7. concentrationconcentrated to dryness under 20 mm Hg at 20° C
8. customThe residue is chromatographed on a column (column diameter: 3 cm, height: 27 cm) of Merck silica gel (0.06-0.2 mm) (50 g)
9. washElution
10. custombeing collected
11. additiona mixture of the starting material
12. concentrationfractions 11 to 17 are concentrated to dryness under 20 mm Hg at 20° C