Diethyl bromomalonate → HCID 20144889, compound

Reaction equation

[S:1]1[C:7]2[CH:8]=[CH:9][S:10][C:6]=2[C:5](=S)[NH:4][CH2:3][CH2:2]1.Br[CH:13]([C:19]([O:21][CH2:22][CH3:23])=[O:20])[C:14]([O:16][CH2:17][CH3:18])=[O:15].C(=O)([O-])O.[K+]>C(Cl)Cl>[S:1]1[C:7]2[C:8](=[C:13]([C:14]([O:16][CH2:17][CH3:18])=[O:15])[C:19]([O:21][CH2:22][CH3:23])=[O:20])[CH2:9][S:10][C:6]=2[CH2:5][NH:4][CH2:3][CH2:2]1

Participants

Procedure

(ca) 8.05 g of 3,4-dihydro-thieno[2,3-f][1,4]thiazepine-5(2H)-thione were suspended in 40 ml of methylene chloride and treated under argon with a solution of 7.1 ml of diethyl bromomalonate in 40 ml of methylene chloride. After stirring for 2.5 hours, 50 ml of 10 percent potassium hydrogen carbonate solution were added thereto and the mixture was stirred for 30 minutes. The organic phase was separated and the aqueous phase was extracted twice with methylene chloride. After drying with sodium sulfate, the extract was chromatographed on silica gel, whereby diethyl [3,4-dihydrothieno[2,3-f][1,4]thiazepine-8-(5H)-ylidene]malonate was obtained in the form of slightly yellowish crystals of m.p. 87°-89° (cyclohexane).