Hydrogen Peroxide → 3-(Difluoromethyl)-1-methyl-1H-pyrazole-4-carboxylic acid

HRID 1627745Notes

Reaction equation

[F:1][CH:2]([F:11])[C:3]1[C:7]([CH:8]=[O:9])=[CH:6][N:5]([CH3:10])[N:4]=1.[OH-:12].[Na+].OO>O>[F:11][CH:2]([F:1])[C:3]1[C:7]([C:8]([OH:12])=[O:9])=[CH:6][N:5]([CH3:10])[N:4]=1

Participants

Conditions

Temperature: 42.5 °C

Procedure

A 3-neck 250 ml round bottomed flask was fitted with a magnetic stirrer and thermometer. Water (130 g), the product of example 1 (compound of formula IX) (6.50 g) and aqueous sodium hydroxide (8.17 g) were charged to the reactor, and the resulting solution heated to 40-45° C. A 35% hydrogen peroxide solution (39 g) was added over 1 hr, and the mixture then stirred at 40-45° C. for 0.5 hr [83% yield of desired product (compound of formula XI)−quantitative HPLC]. The pH of the reaction mass was adjusted to 2.5 by addition of 36% aqueous hydrochloric acid solution. The resulting precipitate was isolated by filtration and washed with water. Drying (60° C., 10 mbar) gave the desired product (XI) as pale yellow, free-flowing powder [69% yield of desired product−quantitative HPLC].

Workup

customA 3-neck 250 ml round bottomed flask was fitted with a magnetic stirrer

Sources & evidence

ORD record: ord-b52c8f1e1beb4b7395421d11cbfb77b2
Source dataset: uspto-grants-2014_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08785657B2

Reaction notes

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