Phosgene → 6-[p-(m-chlorobenzyloxycarbonylamino)-phenyl]-4,5-dihydro-5-methyl-3(2H)-pyridazinone

HRID 1649099Notes

Reaction equation

[Cl:1][C:2]1[CH:3]=[C:4]([CH:7]=[CH:8][CH:9]=1)[CH2:5][OH:6].[C:10](Cl)(Cl)=[O:11].[NH2:14][C:15]1[CH:20]=[CH:19][C:18]([C:21]2[CH:22]([CH3:28])[CH2:23][C:24](=[O:27])[NH:25][N:26]=2)=[CH:17][CH:16]=1>CCOCC.O1CCCC1>[Cl:1][C:2]1[CH:3]=[C:4]([CH:7]=[CH:8][CH:9]=1)[CH2:5][O:6][C:10]([NH:14][C:15]1[CH:20]=[CH:19][C:18]([C:21]2[CH:22]([CH3:28])[CH2:23][C:24](=[O:27])[NH:25][N:26]=2)=[CH:17][CH:16]=1)=[O:11]

Participants

Conditions

Temperature: -10 °C

Procedure

A solution of 7.1 g (49.8 millimoles) of m-chlorobenzyl alcohol in 50 ml of absolute ether is added dropwise to a stirred solution of 11.2 g (113 millimoles) of phosgene in 100 ml of absolute ether at -20° C. The reaction solution is then stirred for 1 hour at -10° C. and for a further hour at room temperature, and thereafter the excess phosgene is removed by means of a dry stream of nitrogen and the other is then removed under reduced pressure at room temperature. The m-chlorobenzyl chloroformate which remains (12.0 g) is dissolved in 50 ml of absolute tetrahydrofuran and the solution is added, at room temperature, to a solution, prepared by the method described in Example 31, of 5.0 g (24.6 millimoles) of 6-(p-aminophenyl)-4,5-dihydro-5-methyl-3(2H)-pyridazinone in 100 ml of absolute tetrahydrofuran. The reaction mixture is then refluxed for 14 hours and is worked up by the method described in Example 31. After recrystallizing the product first from chloroform/petroleum ether, then from acetone/water and finally from propanol/water, 4.0 g (44% of theory) of 6-[p-(m-chlorobenzyloxycarbonylamino)-phenyl]-4,5-dihydro-5-methyl-3(2H)-pyridazinone are obtained as colorless crystals of melting point 165°-166° C.

Workup

customthe excess phosgene is removed by means of a dry stream of nitrogen
customthe other is then removed under reduced pressure at room temperature
dissolutionis dissolved in 50 ml of absolute tetrahydrofuran
additionthe solution is added, at room temperature, to a solution
customprepared by the method
temperatureThe reaction mixture is then refluxed for 14 hours
customAfter recrystallizing the product first from chloroform/petroleum ether

Sources & evidence

ORD record: ord-f29ffe8300f9431da718dd7e293dea86
Source dataset: uspto-grants-1983_11
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04415571

Reaction notes

Loading…