Lithium Hydroxide → 5-(4-Trifluoromethyl-3-pyridyl)-1,2,4-oxadiazole-3-carboxylic acid

HRID 1059499Notes

Reaction equation

C([O:3][C:4]([C:6]1[N:10]=[C:9]([C:11]2[CH:12]=[N:13][CH:14]=[CH:15][C:16]=2[C:17]([F:20])([F:19])[F:18])[O:8][N:7]=1)=[O:5])C.[OH-].[Li+]>CO.O>[F:20][C:17]([F:18])([F:19])[C:16]1[CH:15]=[CH:14][N:13]=[CH:12][C:11]=1[C:9]1[O:8][N:7]=[C:6]([C:4]([OH:5])=[O:3])[N:10]=1

Participants

Conditions

Temperature: 0 °C

Procedure

15.8 g of 3-ethoxycarbonyl-5-(4-trifluoromethyl-3-pyridyl)-1,2,4-oxadiazole are initially charged in 13 ml of methanol, and, with ice-cooling at 0° C., a solution of 2.8 g of lithium hydroxide in 50 ml of water is added dropwise. The mixture is stirred at room temperature for 2 h, 20 ml of ice-water are added and the mixture is extracted with 200 ml of diethyl ether. The aqueous phase is adjused to pH═2 using dil. HCl, and the precipitated product is filtered off with suction. After drying, 13.8 g of 5-(4-trifluoromethyl-3-pyridyl)-1,2,4-oxadiazole-3-carboxylic acid are obtained as a white solid of mp. 157-159° C.

Workup

extractionthe mixture is extracted with 200 ml of diethyl ether
filtrationthe precipitated product is filtered off with suction
customAfter drying

Sources & evidence

ORD record: ord-8a7a297f53fc411aad92d508b7ac6700
Source dataset: uspto-grants-2003_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06521610B2

Reaction notes

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