Hydrochloric Acid → 3-bromo-4,5-dimethyl-4,5-dihydro-6H-cyclopenta[b]thiophen-6-one

HRID 252685Notes

Reaction equation

[Al+3].[Cl-].[Cl-].[Cl-].[CH3:5][CH:6]1[C:13]2[CH:12]=[CH:11][S:10][C:9]=2[C:8](=[O:14])[CH:7]1[CH3:15].[Br:16]Br.Cl>C(Cl)(Cl)Cl>[Br:16][C:12]1[C:13]2[CH:6]([CH3:5])[CH:7]([CH3:15])[C:8](=[O:14])[C:9]=2[S:10][CH:11]=1

Participants

Conditions

Temperature: 0 °C

Procedure

To a suspension of 29.3 g (220 mmol) of AlCl3 in 40 ml of chloroform a solution of 16.4 g (100 mmol) of 4,5-dimethyl-4,5-dihydro-6H-cyclopenta[b]thiophen-6-one in 15 ml of chloroform was added while vigorously stirring for 30 min at 0° C. This mixture was stirred for 15 min; then, a solution of 5.48 ml (17.1 g, 107 mmol) of bromine in 10 ml of chloroform was added dropwise over 1 h at 0° C. The resulting mixture was stirred for 1.5 h at room temperature and then poured on 200 cm3 of ice. The mixture was acidified with 4 M HCl to pH 1. The organic layer was separated, and the aqueous layer was washed with 3×100 ml of dichloromethane. The combined organic fractions were dried over K2CO3 and evaporated to dryness. The product was isolated by vacuum distillation, bp 110-112° C./2 mm Hg. Yield 22.1 g (91%).

Workup

additionwas added
stirringThis mixture was stirred for 15 min
stirringThe resulting mixture was stirred for 1.5 h at room temperature
customThe organic layer was separated
washthe aqueous layer was washed with 3×100 ml of dichloromethane
dry with materialThe combined organic fractions were dried over K2CO3
customevaporated to dryness
customThe product was isolated by vacuum distillation, bp 110-112° C./2 mm Hg

Sources & evidence

ORD record: ord-729a5405b2484f6c994f2c65b7e9f283
Source dataset: uspto-grants-2011_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07868197B2

Reaction notes

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