Water → 5-Chloro-1-(oxan-4-yl)-1h-pyrazole-4-carboxylic acid

HRID 12884Notes

Reaction equation

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

Participants

Conditions

Temperature: 80 °C

Procedure

5-Chloro-1-(tetrahydro-pyran-4-yl)-1H-pyrazole-4-carboxylic acid ethyl ester (2.194 g (98%), 8.31 mmol) was dissolved in methanol (12.5 mL). Lithium hydroxide (0.274 g, 11.44 mmol) and water (12.5 mL) were added and the mixture was heated at 80° C. for 1 hour. After cooling to room temperature, the mixture was concentrated to remove the methanol. Tetrahydrofuran was added to the residue and removed in vacuo to ensure complete removal of the methanol. The aqueous residue was treated with 6N HCl (1.88 mL) resulting in the precipitation of a thick milky solid. The solid was collected by filtration, washed with water and dried under high vacuum with heat to give 5-chloro-1-(tetrahydro-pyran-4-yl)-1H-pyrazole-4-carboxylic acid (1.900 g, 99%). Mass spectrum: m/z: 231.30 (M+H).

Workup

temperatureAfter cooling to room temperature
concentrationthe mixture was concentrated
customto remove the methanol
additionTetrahydrofuran was added to the residue
customremoved in vacuo
customremoval of the methanol
additionThe aqueous residue was treated with 6N HCl (1.88 mL)
customresulting in the precipitation of a thick milky solid
filtrationThe solid was collected by filtration
washwashed with water
customdried under high vacuum
temperaturewith heat

Sources & evidence

ORD record: ord-b4405faa9df24fa68cec7694e881028c
Source dataset: uspto-grants-2010_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07728029B2

Reaction notes

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