Sulfuric Acid → 2-(4-Chloro-2-fluoro-5-hydroxyphenyl)-4-methyl-5-(trifluoromethyl)-3(2H)-pyridazinone

HRID 1421622Notes

Reaction equation

S(=O)(=O)(O)O.[Cl:6][C:7]1[C:12]([O:13]C(C)C)=[CH:11][C:10]([N:17]2[C:22](=[O:23])[C:21]([CH3:24])=[C:20]([C:25]([F:28])([F:27])[F:26])[C:19](C(OCC)=O)=[N:18]2)=[C:9]([F:34])[CH:8]=1>O>[Cl:6][C:7]1[C:12]([OH:13])=[CH:11][C:10]([N:17]2[C:22](=[O:23])[C:21]([CH3:24])=[C:20]([C:25]([F:27])([F:26])[F:28])[CH:19]=[N:18]2)=[C:9]([F:34])[CH:8]=1

Participants

Conditions

Temperature: 130 °C

Procedure

Three mililiters (3 ml) of a mixture of sulfuric acid and water (v/v=2/1), and 1.5 g of 2-(4-chloro-2-fluoro-5-isopropoxyphenyl)-6-ethoxycarbonyl-4-methyl-5-trifluoromethylpyridazin-3-one (the present compound 1-31) were mixed and heated for 6 hours on a 130° C. oil bath. The reaction solution was cooled to room temperature, poured into 50 ml of water. The precipitated crystals were filtered off and washed with 50 ml of water twice. The crystals were dissolved with 100 ml of ethyl acetate and dried over anhydrous magnesium sulfate. The solvent was removed under reduced pressure and the obtained crystals were washed with 20 ml of n-hexane to afford 0.55 g of 2-(4-chloro-2-fluoro-5-hydroxyphenyl)-4methyl-5-trifluoromethylpyridazin-3-one (yield:50%).

Workup

temperatureThe reaction solution was cooled to room temperature
filtrationThe precipitated crystals were filtered off
washwashed with 50 ml of water twice
dissolutionThe crystals were dissolved with 100 ml of ethyl acetate
dry with materialdried over anhydrous magnesium sulfate
customThe solvent was removed under reduced pressure
washthe obtained crystals were washed with 20 ml of n-hexane

Sources & evidence

ORD record: ord-489a1b74713d48e28e5d28c5f5b8cb2b
Source dataset: uspto-grants-2000_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06077953

Reaction notes

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