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

HRID 1017181Notes

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-e40b43423b0e45bcb0da1318f0e26a42
Source dataset: uspto-grants-2002_11
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06479435B1

Reaction notes

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