反应详情

温度

0 °C

Triethylamine (1.01 g, 0.010 mole) was added to a stirred mixture of 5-methylsulfonyl-2-methoxybenzoic acid (2.30 g, 0.010 mole) in 50 ml of methylene chloride. The mixture was cooled to 0° C. for 20 minutes and maintained at this temperature while ethyl chloroformate (1.09 g, 0.010 mole) was added dropwise. After another 20 minutes of stirring at 0° C., a solution of 1,2-diethyl-4-aminopyrazolidine (2.43 g, 0.010 mole) in 10 l of methylene chloride was added dropwise. The reaction mixture was allowed to come to ambient temperature and was stirred for 18 hrs. The reaction mixture was then extracted with 10% sodium bicarbonate solution, the methylene chloride layer separated and dried over magnesium sulfate. The methylene chloride solution was concentrated to give 3.90 g of a tanbrown solid which was recrystallized from water. A sulfate salt was prepared which was converted back to the free base. The solid free base that formed was recrystallized from ethanol-isopropyl ether to give 1.03 g (29%) of title compound; m.p. 123°-124° C. The compound was vacuum dried at 110° C.; the melting point was unchanged.

1. additionwas added dropwise
2. customto come to ambient temperature
3. stirringwas stirred for 18 hrs
4. extractionThe reaction mixture was then extracted with 10% sodium bicarbonate solution
5. customthe methylene chloride layer separated
6. dry with materialdried over magnesium sulfate
7. concentrationThe methylene chloride solution was concentrated