Benzyl (2-(2,4-dichlorobenzenesulfonylamino)-1-{2-(4-chlorophenyl)-1-[(2,2-diethoxyethyl)isopropylcarbamoyl]ethylcarbamoyl}ethyl)carbamate → Benzyl [6-(4-chlorobenzyl)-1-(2,4-dichlorobenzenesulfonyl)-8-isopropyl-4,7-dioxooctahydropyrazino[1,2-a]pyrimidin-3-yl]carbamate

Participants

Reaction Steps

A solution of 2.74 g (3.49 mmol) of benzyl[1-{2-(4-chlorophenyl)-1-[(2,2-diethoxyethyl)-isopropylcarbamoyl]ethylcarbamoyl}-2-(2,4-dichlorobenzenesulfonylamino)ethyl]-carbamate in 45 ml of formic acid was heated at 60° C. for 6 h. The reaction mixture was then concentrated in vacuo, and the residue was purified by chromatography on 40 g of SiO2 (eluent DCM followed by 20% EtOAc/DCM). 2.25 g of the cyclized compound are obtained as a colorless solid.

Provenance & Evidence