반응 #54387

반응 방정식

2-[4-(p-toluenesulphonylthio)-3-phenylacetamido-2-oxoazetidin-1-yl]-3-methoxy-crotonic acid diphenylmethyl ester

1,2-dimethoxyethane

1,5-diazabicyclo[5.4.0]undec-5-ene

→

7β-phenylacetamido-3-methoxy-ceph-2-em-4α-carboxylic acid diphenylmethyl ester

용매

toluene

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후처리

1. 1
   세척washed successively with 2 N hydrochloric acid, saturated aqueous sodium bicarbonate solution and saturated aqueous sodium chloride solution
2. 2
   건조dried over sodium sulphate
3. 3
   농축concentrated by evaporation in vacuo

실험 절차

A mixture of 670 mg (1 mmol) of 2-[4-(p-toluenesulphonylthio)-3-phenylacetamido-2-oxoazetidin-1-yl]-3-methoxy-crotonic acid diphenylmethyl ester, 6.7 ml of 1,2-dimethoxyethane and 0.22 ml of 1,5-diazabicyclo[5.4.0]undec-5-ene is stirred for 25 minutes at room temperature under a nitrogen atmosphere. The reaction mixture is diluted with toluene, washed successively with 2 N hydrochloric acid, saturated aqueous sodium bicarbonate solution and saturated aqueous sodium chloride solution, dried over sodium sulphate and concentrated by evaporation in vacuo. The residue, after preparative thick layer chromatography on silica gel using toluene/ethyl acetate, 1:1, gives 7β-phenylacetamido-3-methoxy-ceph-2-em-4α-carboxylic acid diphenylmethyl ester of melting point 166-169° C. (from methylene chloride/hexane), UV spectrum (ethanol): λmax = 258 mμ (ε = 4,500) IR spectrum (methylene chloride): characteristic bands at 2.93, 5.62, 5.73, 5.93 and 6.66 μ, Rf value~0.54 (silica gel; system toluene/ethyl acetate, 1:1), and amorphous 7β-phenylacetamido-3-methoxy-ceph-3-em-4-carboxylic acid diphenylmethyl ester, UV spectrum (ethanol): λmax =258 mμ (ε = 6,350), 264 mμ (ε = 6,350), 282 mμ (ε = 5,600) (shoulder), IR spectrum (methylene chloride): characteristic bands at 2.94, 5.63, 5.83, 5.94, 6.26 and 6.66 μ, Rf value~0.37 (silica gel; system toluene/ethyl acetate, 1:1), in the ratio of 8:1.

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