Reaktion #460049

Reaktionsgleichung

diphenylmethyl 7-(2-thienylacetamido)-3-(1-acetoxyethyl)-3-cephem-4-carboxylate 1-oxide

acetyl chloride

→

diphenylmethyl 7-(2-thienylacetamido)-3-(1-acetoxyethyl)-3-cephem-4-carboxylate

Ausbeute 79.8%

Lösungsmittel

N,N-dimethylformamide

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGthe mixture is stirred with ice for 20 minutes
2. 2
   Extraktionis extracted with ethyl acetate
3. 3
   WaschenThe extract solution is washed with aqueous sodium hydrogen carbonate and saline
4. 4
   Trocknendried over sodium sulfate
5. 5
   Sonstigeevaporated
6. 6
   SonstigeRecrystallization of the residue (81 mg) from petroleum ether

Vorschrift

To a solution of non-polar stereoisomer A of diphenylmethyl 7-(2-thienylacetamido)-3-(1-acetoxyethyl)-3-cephem-4-carboxylate 1-oxide (85 mg) in N,N-dimethylformamide (2.5 ml) is added under ice cooling stannous chloride dihydrate (81 mg) with stirring. Ten minutes after the addition of acetyl chloride (0.34 mg), the mixture is stirred with ice for 20 minutes. The reaction mixture is poured into ice water, and is extracted with ethyl acetate. The extract solution is washed with aqueous sodium hydrogen carbonate and saline, dried over sodium sulfate, and evaporated. Recrystallization of the residue (81 mg) from petroleum ether gives the stereoisomer A of diphenylmethyl 7-(2-thienylacetamido)-3-(1-acetoxyethyl)-3-cephem-4-carboxylate (66 mg). m.p. 77°-85° C. Yield: 79.8%. IR: νmaxCHCl 3 3405, 1789, 1728, 1685, 1509 cm-1. NMR: δCDCl 3 1.34d(6.5Hz)3H, 1.98s3H, 3.37s2H, 3.82s2H, 4.96d(5Hz)1H, 5.79q (8.5;5Hz)1H, 5.99q(6.5Hz)1H, 6.32d(8.5Hz)1H, 6.8-7.5m14H.

Quelle