Lithium Hydroxide → (E)-3-cyclopentyl-2-(3,4-dichloro-phenyl)-acrylic acid

HRID 276194Notes

Reaction equation

C[O:2][C:3](=[O:19])[C:4]([C:11]1[CH:16]=[CH:15][C:14]([Cl:17])=[C:13]([Cl:18])[CH:12]=1)=[CH:5][CH:6]1[CH2:10][CH2:9][CH2:8][CH2:7]1.[OH-].[Li+]>O1CCCC1>[CH:6]1(/[CH:5]=[C:4](\[C:11]2[CH:16]=[CH:15][C:14]([Cl:17])=[C:13]([Cl:18])[CH:12]=2)/[C:3]([OH:19])=[O:2])[CH2:10][CH2:9][CH2:8][CH2:7]1

Participants

Conditions

Temperature: 25 °C

Procedure

A solution of the isomeric mixture of 3-cyclopentyl-2-(3,4-dichloro-phenyl)-acrylic acid methyl ester [821.1 mg, 2.74 mmol, (E):(Z)=4.5:1] in tetrahydrofuran (3.4 mL) was treated with a 0.8M aqueous lithium hydroxide solution (3.4 mL, 2.74 mmol). The reaction mixture was stirred at 25° C. for 17 h and then heated under reflux for 4 h. The reaction mixture was allowed to cool to 25° C. and then concentrated in vacuo to remove tetrahydrofuran. The remaining aqueous layer was acidified to pH=2 with a 10% aqueous hydrochloric acid solution and then extracted with ethyl acetate (2×150 mL). The combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo. Flash chromatography (Merck Silica gel 60, 70-230 mesh, 1/1 hexanes/ethyl acetate) afforded pure (E)-3-cyclopentyl-2-(3,4-dichloro-phenyl)-acrylic acid (205.4 mg, 26%) as a white solid: mp 119-120° C.; EI-HRMS m/e calcd for C14H14Cl2O2 (M+) 284.0371, found 284.0370.

Workup

temperatureheated
temperatureunder reflux for 4 h
temperatureto cool to 25° C.
concentrationconcentrated in vacuo
customto remove tetrahydrofuran
extractionextracted with ethyl acetate (2×150 mL)
dry with materialThe combined organic layers were dried over sodium sulfate
filtrationfiltered
concentrationconcentrated in vacuo

Sources & evidence

ORD record: ord-9d8ac84a412441458e403e7513549b8d
Source dataset: uspto-grants-2002_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06353111B1

Reaction notes

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