Reaktion #6386

Reaktionsgleichung

methanol

Phosphorus pentachloride

t-butyl (6R,7R)-3-[(5S)-2-oxotetrahydrofuran-5-yl]-7-phenoxyacetamido-ceph-3-em-4-carboxylate

N-methylmorpholine

→

title compound

Ausbeute 40.1%

t-Butyl (6R,7R)-7-amino-3-[(5S)-2-oxo-tetrahydrofuran-5-yl]ceph-3-em-4-carboxylate

Ausbeute 40.1%

Lösungsmittel

water

dichloromethane

dichloromethane

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGStirring
2. 2
   workup.WAITwas continued for 0.75 h
3. 3
   Temperaturwithout further cooling
4. 4
   workup.STIRRINGthe mixture was stirred vigorously for 1 h
5. 5
   SonstigeThe dichloromethane was removed in vacuo, ethyl acetate (ca 10 ml)
6. 6
   workup.ADDITIONadded
7. 7
   Extraktionextracted twice with ethyl acetate
8. 8
   WaschenThe extracts were washed with brine
9. 9
   Sonstigedried
10. 10
    Einengenconcentrated
11. 11
    Sonstigeflash chromatographed
12. 12
    Wascheneluting with 40,50,75% ethyl acetate in hexane

Vorschrift

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).

Quelle