Hydrochloric Acid → Diphenylmethyl [4-[3-(4-thiocarbamoylbenzenesulfonylamino)propyl]-2,3-dioxopiperazin-1-yl]acetate

Participants

Reaction Steps

Hydrogen sulfide gas was introduced into a mixture of 0.48 g of diphenylmethyl [4-[3-(4-cyanobenzenesulfonylamino)propyl]-2,3-dioxopiperazin-1-yl]-acetate, 2.4 ml of triethylamine and 4.8 ml of pyridine at room temperature until the mixture was saturated therewith. After stirring at the same temperature for 5 hours, the reaction mixture was added to a mixed solvent of 30 ml of ethyl acetate and 30 ml of water, and the pH was adjusted to 4 with 6N hydrochloric acid. The organic layer was separated and the aqueous layer was re-extracted with 10 ml of ethyl acetate. The combined organic layer was washed with water and then a saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, and then distilled under reduced pressure to remove the solvent. The resulting residue was purified by a silica gel column chromatography (eluent; chloroform:methanol=20:1) to obtain 0.40 g of diphenylmethyl [4-[3-(4-thiocarbamoylbenzenesulfonylamino)propyl]-2,3-dioxopiperazin-1-yl]acetate as yellow crystals.

Provenance & Evidence