反应详情

To a suspension of potassium (49.2 g, 1.26 mol) in anhydrous diethyl ether (500 ml), a solution of absolute EtOH (319 ml) and anhydrous diethyl ether (260 ml) was added dropwise under nitrogen during a period of four hours. The resulting solution was diluted with anhydrous diethyl ether (1200 mL) and then diethyl oxalate (171 ml, 1.26 mol) was added dropwise in about 30 minutes. To the resulting yellow mixture, a solution of 2-nitro-4,5-dichlorotoluene (260 g, 1.26 mmol), prepared as described by Cohen and Dakin in J. Chem. Soc., 79, 1133, in anhydrous diethyl ether (450 ml) was added dropwise in one hour at RT. Stirring was continued for additional three hours and the dark-brown mixture was settled at RT for two days. The potassium salt was collected by suction and dried to give a dark-brown powder. This was suspended in a mixture of water (400 ml) and ethyl acetate (400 ml), then acidified with 10% HCl. The organic phase was washed with brine, aqueous sat. NaHCO3 and again brine, then it was dried with MgSO4. Evaporation produced 239 g of title compound (781 mmol, yield 62.0%) as a light brown solid that was used as such for the next step, m.p.=92-94° C.

1. waitthe dark-brown mixture was settled at RT for two days
2. customThe potassium salt was collected by suction
3. customdried
4. customto give a dark-brown powder
5. washThe organic phase was washed with brine, aqueous sat. NaHCO3 and again brine
6. dry with materialit was dried with MgSO4
7. customEvaporation