反应详情

Triethylamine (0.70 ml, 5 mmole) and a solution of methanethiol (2.8 ml, ca. 10 equiv.) in dimethylformamide (10 ml,), previously cooled to -30°, were added to a solution of 2,2,2-trichloroethyl-3-bromomethyl-7β-phenylacetamidoceph-3-em-4-carboxylate, 1β-oxide (2.79 g, 5 mmole) in dimethylformamide (40 ml) cooled to -30°. The reaction solution was allowed to warm to 20° and then stirred at this temperature for 30 minutes then dilution of an aliquot with ethanol gave a solution with λmax. 274 nm. Nitrogen was passed through the dimethylformamide solution for 45 minutes to remove the excess of thiol and potassium iodide (5 g.) and acetyl chloride (5 ml.) were added. After 4 hours at 20°, t.l.c. (acetone-methylene chloride, 1:15) showed that reduction was complete. The solution was cooled in an ice-bath, and 0.1 N-sodium thiosulphate solution was added until the solution became pale-yellow. Methylene chloride and water (80 ml of each) were added and the aqueous layer was separated and reextracted with methylene chloride (100 ml.). The combined methylene chloride layers were washed with water (3 × 100 ml.), dried and evaporated to give the title ester as a solvated yellow gelatinous solid (2.76 g), λmax. 268 nm (E1cm1% 133).

1. temperaturecooled to -30°
2. temperatureto warm to 20°
3. customto remove the excess of thiol and potassium iodide (5 g.) and acetyl chloride (5 ml.)
4. additionwere added
5. waitAfter 4 hours at 20°
6. temperatureThe solution was cooled in an ice-bath
7. addition0.1 N-sodium thiosulphate solution was added until the solution
8. additionMethylene chloride and water (80 ml of each) were added
9. customthe aqueous layer was separated
10. washThe combined methylene chloride layers were washed with water (3 × 100 ml.)
11. customdried
12. customevaporated