L-Pyroglutamic Acid → HCID 178516174, compound

Participants

Reaction Conditions

Reaction Steps

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.

Provenance & Evidence