Lithium Hydroxide → 1-tert-butyl-5-(5-chloro-isoxazol-3-yl)-1H-pyrazole-4-carboxylic acid

HRID 12877Notes

Reaction equation

C([O:3][C:4]([C:6]1[CH:7]=[N:8][N:9]([C:17]([CH3:20])([CH3:19])[CH3:18])[C:10]=1[C:11]1[CH:15]=[C:14]([Cl:16])[O:13][N:12]=1)=[O:5])C.[OH-].[Li+]>C(O)C>[C:17]([N:9]1[C:10]([C:11]2[CH:15]=[C:14]([Cl:16])[O:13][N:12]=2)=[C:6]([C:4]([OH:5])=[O:3])[CH:7]=[N:8]1)([CH3:20])([CH3:18])[CH3:19]

Participants

Conditions

Temperature: 25 °C

Procedure

A solution of 1-tert-butyl-5-(5-chloro-isoxazol-3-yl)-1H-pyrazole-4-carboxylic acid ethyl ester (55.3 mg, 0.18 mmol) in absolute ethanol (0.93 mL, 0.2M) was treated with a 2M aqueous lithium hydroxide solution (0.18 mL, 0.37 mmol). The reaction was stirred at 25° C. for 1.5 h and then was heated to 100° C. for 1 h. At this time, the reaction was allowed to cool to 25° C. and was stirred at 25° C. overnight. At this time, the reaction was concentrated in vacuo. The residue was treated with water followed by acidification to pH=1 with a 1N aqueous hydrochloric acid solution. The resulting precipitate that formed was collected by filtration, washed with water and hexanes and dried in vacuo to afford 1-tert-butyl-5-(5-chloro-isoxazol-3-yl)-1H-pyrazole-4-carboxylic acid (38.7 mg, 77%) as an off-white solid.

Workup

temperaturewas heated to 100° C. for 1 h
temperatureto cool to 25° C.
stirringwas stirred at 25° C. overnight
concentrationAt this time, the reaction was concentrated in vacuo
additionThe residue was treated with water
customThe resulting precipitate that formed
filtrationwas collected by filtration
washwashed with water and hexanes
customdried in vacuo

Sources & evidence

ORD record: ord-91730036d6fa4ebeb4f0f77293c28356
Source dataset: uspto-grants-2010_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07728029B2

Reaction notes

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