反应 #1543064

反应方程式

3,3-dibromo-alpha-(1-methylethylidene)-2-[(5-methyl-isoxazole-3-yl)-aminosulfinyl]-4-oxo-1-azetidine acetic acid benzyl ester

N-bromosuccinimide

→

2,3,3-tribromo-alpha-(1-methylethylidene)-4-oxo-1-azetidine acetic acid benzyl ester

收率 61.5%

溶剂

chloroform

反应条件

后处理

1. 1
   其他The reaction mixture was evaporated
2. 2
   workup.ADDITIONmethylene chloride and n-hexane were added to the dry residue
3. 3
   其他the filtrate was evaporated to a dry residue
4. 4
   其他The obtained product was purified by flash chromatography with the solvent system petroleum ether-methylene chloride (1:1)

实验过程

3,3-dibromo-alpha-(1-methylethylidene)-2-[(5-methyl-isoxazole-3-yl)-aminosulfinyl]-4-oxo-1-azetidine acetic acid benzyl ester (5.61 g; 0.01 mole) was dissolved in chloroform (120 mL), N-bromosuccinimide (7.12 g; 0.04 mole) was added to the reaction mixture and it was stirred for two hours at room temperature. The reaction mixture was evaporated, methylene chloride and n-hexane were added to the dry residue, the precipitate was sucked off and the filtrate was evaporated to a dry residue. The obtained product was purified by flash chromatography with the solvent system petroleum ether-methylene chloride (1:1). There was obtained 2,3,3-tribromo-alpha-(1-methylethylidene)-4-oxo-1-azetidine acetic acid benzyl ester (3.05 g, 61.5%), which was subjected to a reaction with silver tetrafluoroborate in methanol analogously to the reaction described under 1a. After isolation 3,3-dibromo-2-methoxy-alpha-(1-methylethylidene)-4-oxo-1-azetidine acetic acid benzyl ester with spectroscopic data identical to those disclosed under 1a was obtained.

来源