Stannous Chloride → 5-(2-Amino-4-methyl-phenylamino)-1-methyl-1H-pyrazole-4-carboxylic Acid Ethyl Ester

HRID 220763Notes

Reaction equation

[Sn](Cl)Cl.[CH2:4]([O:6][C:7]([C:9]1[CH:10]=[N:11][N:12]([CH3:25])[C:13]=1[NH:14][C:15]1[CH:20]=[CH:19][C:18]([CH3:21])=[CH:17][C:16]=1[N+:22]([O-])=O)=[O:8])[CH3:5]>CO>[CH2:4]([O:6][C:7]([C:9]1[CH:10]=[N:11][N:12]([CH3:25])[C:13]=1[NH:14][C:15]1[CH:20]=[CH:19][C:18]([CH3:21])=[CH:17][C:16]=1[NH2:22])=[O:8])[CH3:5]

Participants

Conditions

Temperature: 0 °C

Procedure

Tin (II) chloride (86.65 g, 457.0 mmol) was added to a solution of 1-methyl-5-(4-methyl-2-nitro-phenylamino)-1H-pyrazole-4-carboxylic acid ethyl ester from Example E2.1 (28.00 g, 91.4 mmol) in methanol and the mixture heated at reflux for 3 days. The solvent was removed in vacuo and the residue taken up in EtOAc (400 ml) and cooled to 0° C. 35% Ammonia solution was added to pH 14, and the mixture was stirred for 15 min before being filtered through Celite® filter agent. The filtrate was washed with 2M NH3 and brine and concentrated in vacuo. The residue was purified by flash chromatography on silica gel (eluant; 6% methanol:94% dichloromethane rising to 10% methanol:90% dichloromethane) to yield the title compound (12.8 g, 52%).

Workup

temperaturethe mixture heated
temperatureat reflux for 3 days
customThe solvent was removed in vacuo
addition35% Ammonia solution was added to pH 14
filtrationbefore being filtered through Celite®
filtrationfilter agent
washThe filtrate was washed with 2M NH3 and brine
concentrationconcentrated in vacuo
customThe residue was purified by flash chromatography on silica gel (eluant; 6% methanol:94% dichloromethane rising to 10% methanol:90% dichloromethane)

Sources & evidence

ORD record: ord-47d10ad22b164376955eb3aafc5acd41
Source dataset: uspto-grants-2012_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08202858B2

Reaction notes

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