반응 #54382

반응 방정식

2-[4-(benzthiazol-2-yldithio)-3-phenoxyacetamido-2-oxoazetidin-1-yl ]-3-methoxy-crotonic acid chloride

triethylamine

tert.-butanol

2-[4-(benzthiazol-2-yldithio)-3-phenoxyacetamido-2-oxoazetidin-1-yl]-3-methoxy-isocrotonic acid chloride

→

7β-Phenoxyacetamido-3-methoxy-ceph-2-em-4-carboxylic acid tert.butyl ester

용매

methylene chloride

methylene chloride

methylene chloride

반응 조건

후처리

1. 1
   workup.ADDITIONis added dropwise over the course of 15 minutes at 0° C.
2. 2
   세척washed with water, with dilute hydrochloric acid and again with water
3. 3
   건조dried over sodium sulphate
4. 4
   농축concentrated by evaporation in vacuo
5. 5
   기타The residue is chromatographed on 10 g of acid-washed silica gel

실험 절차

A solution of 266 mg (0.5 mM) of a crude mixture consisting of 2-[4-(benzthiazol-2-yldithio)-3-phenoxyacetamido-2-oxoazetidin-1-yl ]-3-methoxy-crotonic acid chloride and 2-[4-(benzthiazol-2-yldithio)-3-phenoxyacetamido-2-oxoazetidin-1-yl]-3-methoxy-isocrotonic acid chloride in 5 ml of dry methylene chloride is added dropwise over the course of 15 minutes at 0° C., whilst stirring, to a solution of 0.10 ml of triethylamine in 0.5 ml of dry tert.-butanol and 3 ml of methylene chloride. After a further 15 minutes stirring, the reaction mixture is diluted with methylene chloride, washed with water, with dilute hydrochloric acid and again with water, dried over sodium sulphate and concentrated by evaporation in vacuo. The residue is chromatographed on 10 g of acid-washed silica gel, using toluene/ethyl acetate (4:1) as the running agent. 7β-Phenoxyacetamido-3-methoxy-ceph-2-em-4-carboxylic acid tert.butyl ester is obtained. IR spectrum (in CH2CL2): characteristic bands at 5.60, 5.77, 5.90 and 8.29 μ.

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