Hydrogen Peroxide → 2-(Bromomethyl)-3-(2-chlorophenyl)-2-(2,4-difluorophenyl)oxirane

HRID 508118Notes

Reaction equation

C1(=O)OC(=[O:5])C=C1.OO.[Br:10][CH2:11][C:12]([C:21]1[CH:26]=[CH:25][C:24]([F:27])=[CH:23][C:22]=1[F:28])=[CH:13][C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][C:15]=1[Cl:20]>C(O)(=O)C>[Br:10][CH2:11][C:12]1([C:21]2[CH:26]=[CH:25][C:24]([F:27])=[CH:23][C:22]=2[F:28])[CH:13]([C:14]2[CH:19]=[CH:18][CH:17]=[CH:16][C:15]=2[Cl:20])[O:5]1

Participants

Conditions

Temperature: 40 °C

Procedure

Maleic anhydride (2.05 g, 20.9 mmol) and then hydrogen peroxide (35% by weight strength solution, 2.04 g, 20.9 mmol) were added to a stirred solution of 1-[3-bromo-1-(2-chlorophenyl)prop-1-en-2-yl]-2,4-difluorobenzene (720 mg, 2.09 mmol) in acetic acid (20 ml). The reaction mixture was stirred at 40° C. for 24 h, more hydrogen peroxide (35% by weight strength solution, 2.04 g, 20.9 mmol) was then added and the reaction mixture was stirred at 20° C. for 66 h. Excess oxidizing agent was quenched by addition of sat. aq. sodium thiosulphate. The mixture was extracted with dichloromethane, and the organic phase was dried over MgSO4 and concentrated under reduced pressure. Purification of the residue on silica gel gave 2-(bromomethyl)-3-(2-chlorophenyl)-2-(2,4-difluorophenyl)oxirane as a 59/41 mixture of diastereoisomers [316 mg, colourless oil, yield 40%; GC/MS: m/z=279 ([M-Br]+); HPLC/MS: log P(HCOOH)=4.61 (major diastereoisomer), 5.00 (minor diastereoisomer)].

Workup

stirringthe reaction mixture was stirred at 20° C. for 66 h
customwas quenched by addition of sat. aq. sodium thiosulphate
extractionThe mixture was extracted with dichloromethane
dry with materialthe organic phase was dried over MgSO4
concentrationconcentrated under reduced pressure
customPurification of the residue on silica gel

Sources & evidence

ORD record: ord-009c604dabf2486f90c4297f6c42024e
Source dataset: uspto-grants-2015_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09095136B2

Reaction notes

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