反应详情

At 0°-5° C., 1.2 g of a sodium hydride dispersion (80 %) are added in portions to a solution of 8.6 g of 4-hydroxy-pyrazolidine-N,N'-dicarboxylic acid di-tert-butyl ester in 90 ml of N,N-dimethylformamide. After stiffing for 30 minutes at 0°-5° C., a solution of 2.5 ml of methyl iodide in 10 ml of N,N-dimethylformamide is added dropwise thereto. Stirring is then continued for 3 hours at 0°-5° C. and then 500 ml of diethyl ether are added thereto. The organic phase is washed with water, dried over sodium sulfate and concentrated to yield 8.0 g of the desired product, 4-methoxy-pyrazolidine-N,N'-dicarboxylic acid di-tertbutyl ester, in the form of a yellow oil.

1. waitis then continued for 3 hours at 0°-5° C.
2. washThe organic phase is washed with water
3. dry with materialdried over sodium sulfate
4. concentrationconcentrated