反应详情

温度

-15 °C

Phosphorus pentachloride (0.35 g,1.7 mmol) in dichloromethane (9 ml) was added to t-butyl (6R,7R)-3-[(5S)-2-oxotetrahydrofuran-5-yl]-7-phenoxyacetamido-ceph-3-em-4-carboxylate (0.526 g, 1.1 mmol) and N-methylmorpholine (0.24 ml, 2.2 mmol) in dichloromethane (15 ml) at <-20° C. The reaction was stirred at -15±5° C. for 0.75 h then methanol (3 ml) was added. Stirring was continued for 0.75 h without further cooling and then water (10 ml) was added and the mixture was stirred vigorously for 1 h. The dichloromethane was removed in vacuo, ethyl acetate (ca 10 ml) added, the mixture adjusted to pH5.5 with dilute ammonium hydroxide solution and extracted twice with ethyl acetate. The extracts were washed with brine, dried, concentrated and flash chromatographed, eluting with 40,50,75% ethyl acetate in hexane, to give the title compound as a foam (0.15 g,40%); (Found: M+, 340.1097. C15H20N2O5S requires M, 340.1093); νmax (CH2Cl2) 1770,1710,1362,1350,1235 and 1170 cm-1 ; δH (CDCl3) 1.54 (9H,s), 1.9-2.1 (1H,m), 2.5-2.8 (3H,m), 3.27 and 3.56 (2H,ABq,J18.5 Hz), 4.80 (1H,d,J5Hz), 4.96 (1H,d,J5 Hz), 5.6-5.7 (1H,m).

1. stirringStirring
2. waitwas continued for 0.75 h
3. temperaturewithout further cooling
4. stirringthe mixture was stirred vigorously for 1 h
5. customThe dichloromethane was removed in vacuo, ethyl acetate (ca 10 ml)
6. additionadded
7. extractionextracted twice with ethyl acetate
8. washThe extracts were washed with brine
9. customdried
10. concentrationconcentrated
11. customflash chromatographed
12. washeluting with 40,50,75% ethyl acetate in hexane