Hydrochloric Acid → 4-chloro-5-(2-trifluoromethyl-phenoxy)-2H-pyridazin-3-one

HRID 2381482Notes

Reaction equation

[Cl:1][C:2]1[C:3](=[O:25])[N:4](C2CCCCO2)[N:5]=[CH:6][C:7]=1[O:8][C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][C:10]=1[C:15]([F:18])([F:17])[F:16].Cl>CO.O>[Cl:1][C:2]1[C:3](=[O:25])[NH:4][N:5]=[CH:6][C:7]=1[O:8][C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][C:10]=1[C:15]([F:17])([F:18])[F:16]

Participants

Conditions

Temperature: 110 °C

Procedure

A solution of 4-chloro-2-(tetrahydro-pyran-2-yl)-5-(2-trifluoromethyl-phenoxy)-2H-pyridazin-3-one (4.78 g, 12.78 mmol) in methanol (25.5 mL, 0.5M) was treated with a 6N aqueous hydrochloric acid solution (10.6 mL, 1.2M). The reaction solution was heated to 110° C., where it stirred for 4 h and was then allowed to cool down to 25° C. The reaction was diluted with water (250 mL) and extracted with a 90/10 methylene chloride/methanol solution (3×100 mL). The combined organic layers were dried over sodium sulfate, filtered, and dried in vacuo to afford 4-chloro-5-(2-trifluoromethyl-phenoxy)-2H-pyridazin-3-one (3.76 g, 100%) as a white solid; ES+-HRMS m/e calcd for C11H6N2O2F3Cl [M+H+] 291.0143, found 291.0142. 1H NMR (300 MHz, DMSO-d6) δ ppm 7.41-7.51 (m, 2H), 7.74 (t, J=8.2 Hz, 1H), 7.79 (s, 1H), 7.86 (d, J=7.8 Hz, 1H), 13.59 (br. s., 1H).

Workup

temperatureto cool down to 25° C
extractionextracted with a 90/10 methylene chloride/methanol solution (3×100 mL)
dry with materialThe combined organic layers were dried over sodium sulfate
filtrationfiltered
customdried in vacuo

Sources & evidence

ORD record: ord-9ce872fb35274f6cbdb880791edfe747
Source dataset: uspto-grants-2012_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08258134B2

Reaction notes

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