反应详情

温度

5 °C

2.1 g (0.016 mol) (S)-pyroglutamic acid (2-pyrrolidinone-5-carboxylic acid) are dissolved in 50 ml abs. tetrahydrofuran and 2.5 ml (0.018 mol) triethylamine. With cooling to about 5° C., 2 ml (0.016 mol) pivaloyl chloride in 10 ml abs. tetrahydrofuran are added dropwise thereto. After 15 min stirring at 5° C., one adds dropwise thereto a solution of 3.9 g trans-4-nitroxycyclohexylamine in 40 ml abs. tetrahydrofuran and 2.8 ml (0.02 mol) triethylamine. Thereafter, one allows to stir for 2 d at room temperature, filters off with suction and removes the solvent in a vacuum. The residue is dissolved in ethyl acetate and shaken out with sodium hydrogen carbonate. After drying of the ethyl acetate phase with sodium sulphate, distilling off in a vacuum, trituration with ether and suction filtration, there remain 1.5 g of the title compound of the melting point 166° C., i.e. 35% of theory.

1. additionone adds dropwise
2. stirringto stir for 2 d at room temperature
3. customremoves the solvent in a vacuum
4. dissolutionThe residue is dissolved in ethyl acetate
5. stirringshaken out with sodium hydrogen carbonate
6. dry with materialAfter drying of the ethyl acetate phase with sodium sulphate
7. distillationdistilling off in a vacuum, trituration with ether and suction filtration, there