Hydrochloric Acid → 5-oxothiomorpholine-3-carboxylic Acid

Participants

Reaction Steps

A solution of 1.75 g (10 mmole) of L-cysteine hydrochloride monohydrate dissolved in 50 ml of water was adjusted to pH 8.0 with 1M sodium carbonate. Under nitrogen gas stream, 1.85 g (10 mmole) of monoiodoacetamide and 1M sodium carbonate were added alternately while maintaining pH at 8.0. After the reaction was carried out at room temperature for 1 hour, further the reaction was carried out in a sealed tube at 100° C. for 2 hours. To the reaction mixture was added 4N HCl to adjust the pH to 3.25, followed by concentration to dryness. The residue was extracted with hot ethanol, and after cooling, the crystals were collected by filtration and recrystallized from hot ethanol. Yield: 560 mg (34.8%), melting point: 182° to 184° C., Fab mass analysis [M+H]+= 162.

Provenance & Evidence