Carbon Dioxide → 3-(4-methylphenyl)-2H-1-benzopyran-6-carboxylic acid

HRID 1169352Notes

Reaction equation

Br[C:2]1[CH:3]=[CH:4][C:5]2[O:10][CH2:9][C:8]([C:11]3[CH:16]=[CH:15][C:14]([CH3:17])=[CH:13][CH:12]=3)=[CH:7][C:6]=2[CH:18]=1.C([Li])CCC.[C:24](=[O:26])=[O:25].Cl>C1COCC1.CCCCCC>[CH3:17][C:14]1[CH:15]=[CH:16][C:11]([C:8]2[CH2:9][O:10][C:5]3[CH:4]=[CH:3][C:2]([C:24]([OH:26])=[O:25])=[CH:18][C:6]=3[CH:7]=2)=[CH:12][CH:13]=1

Participants

Conditions

Temperature: -78 °C

Procedure

Into a solution of 6-bromo-3-(4-methylphenyl)-2H-1-benzopyran (0.5 g) in THF (15 ml) was added at −78° C. 1.6 M butyl lithium (a hexane solution) (1.14 ml) under a nitrogen atmosphere. The resulting mixture was stirred at −78° C. for one hour, was then mixed with dry ice and was stirred for additional one hour. After addition of 1 N hydrochloric acid (10 ml), the resulting mixture was extracted with ethyl acetate. The organic layer was washed with an aqueous saturated solution of sodium chloride and was dried with magnesium sulfate. After concentration under reduced pressure, the resulting crystals were collected by filtration, and the crystals were washed with diethyl ether and hexane to obtain 3-(4-methylphenyl)-2H-1-benzopyran-6-carboxylic acid (218 mg) as colorless crystals.

Workup

stirringwas stirred for additional one hour
extractionthe resulting mixture was extracted with ethyl acetate
washThe organic layer was washed with an aqueous saturated solution of sodium chloride
dry with materialwas dried with magnesium sulfate
concentrationAfter concentration under reduced pressure
filtrationthe resulting crystals were collected by filtration
washthe crystals were washed with diethyl ether and hexane

Sources & evidence

ORD record: ord-a7c9f4bc7cf1419f8ffeeeb820bb018c
Source dataset: uspto-grants-2003_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06627651B1

Reaction notes

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