Sulfuric Acid → 2-(4-Chloro-2-fluoro-5-hydroxyphenyl)hexahydro-3-thioxo-1H-[1,2,4]triazolo[1,2-a]pyridazin-1-one

HRID 380303Notes

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:25](=[O:26])[N:20]3[CH2:21][CH2:22][CH2:23][CH2:24][N:19]3[C:18]2=[S:27])=[C:9]([F:28])[CH:8]=1>C(Cl)Cl>[Cl:6][C:7]1[C:12]([OH:13])=[CH:11][C:10]([N:17]2[C:25](=[O:26])[N:20]3[CH2:21][CH2:22][CH2:23][CH2:24][N:19]3[C:18]2=[S:27])=[C:9]([F:28])[CH:8]=1

Participants

Conditions

Temperature: 0 °C

Procedure

Conc. sulfuric acid (22 ml) was added dropwise to a solution of 2-[4-chloro-2-fluoro-5-(isopropyloxy)phenyl]hexahydro-3-thioxo-1H-[1,2,4]triazolo[1,2-a]pyridazin-1-one (17.2 g) in methylene chloride (120 ml) stirred at 0° C. The mixture was stirred at room temperature for 1 hour and ice-water (200 g) added. The aqueous phase was extracted with methylene chloride and the organic phases combined, dried over sodium sulfate and chromatographed (silica gel, ethyl acetate) to give the product (14.5 g, 96%). 1H NMR (CDCl3, TMS): 1.84(4H, m), 3.82(4H, m), 7.06(1H, d, J=6.5 Hz), 7.58(1H, d, J=8.8 Hz), 10.6(1H, s).

Workup

stirringThe mixture was stirred at room temperature for 1 hour
extractionThe aqueous phase was extracted with methylene chloride
dry with materialdried over sodium sulfate
customchromatographed (silica gel, ethyl acetate)

Sources & evidence

ORD record: ord-83dc3c77e6904c5597c305b78b75c0a4
Source dataset: uspto-grants-2001_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06303543B1

Reaction notes

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