反应详情

2-(3-Cyclopenten-1-yloxyimino)-2-(2-formamidothiazol-4-yl)acetic acid (syn isomer, 2.0 g) in tetrahydrofuran (20 ml) was activated with Vilsmeier reagent prepared from N,N-dimethylformamide (0.66 ml) and phosphorus oxychloride (0.72 ml). To a solution of bis(trifluoroacetic acid) salts of 7β-amino-3-(2-methyl-1-pyrazolio)methyl-3-cephem-4-carboxylate (3.70 g) and N-mono(trimethylsilyl)acetanide (18.6 g) in tetrahydrofuran (37 ml) was added the activated acid solution obtained above under ice-cooling. After stirring at the same temperature for 1 hour, the reaction mixture was poured into a mixture of ethyl acetate (200 ml) and diisopropyl ether (200 ml). The solvent was removed by decantation. The residual glassy mass was washed with ethyl acetate by decantation and then dissolved in methanol (40 ml). To the solution was added conc. hydrochloric acid (8.2 ml) and the mixture was stirred at ambient temperature for 2 hours. The resultant solution was concentrated under reduced pressure and the residue was dissolved in water (80 ml). The solution was washed with ethyl acetate twice, and adjusted to pH 2.0 with diluted hydrochloric acid. The solution was subjected to column chromatography on macroporous non-ionic adsorption resin "Diaion HP-20", washed with water, and eluted with a mixture of 40% aqueous methanol. The fractions containing the object compound were collected, concentrated in vacuo and then lyophilized to give 7β-[2-(2-aminothiazol-4-yl)-2-(3-cyclopenten-1-yloxyimino)acetamido]-3-(2-methyl-1-pyrazoliomethyl-3-cephem-4-carboxylate (syn isomer, 1.12 g).

1. customobtained above under ice-
2. temperaturecooling
3. customThe solvent was removed by decantation
4. washThe residual glassy mass was washed with ethyl acetate by decantation
5. dissolutiondissolved in methanol (40 ml)
6. additionTo the solution was added conc. hydrochloric acid (8.2 ml)
7. stirringthe mixture was stirred at ambient temperature for 2 hours
8. concentrationThe resultant solution was concentrated under reduced pressure
9. dissolutionthe residue was dissolved in water (80 ml)
10. washThe solution was washed with ethyl acetate twice
11. washwashed with water
12. washeluted with a mixture of 40% aqueous methanol
13. additionThe fractions containing the object compound
14. customwere collected
15. concentrationconcentrated in vacuo