Maleic Anhydride → 4-[(5-bromo-1H-indazol-3-yl)amino]-4-oxo-2-butenoic acid

HRID 497584Notes

Reaction equation

[C:1]1(=[O:7])[O:6][C:4](=[O:5])[CH:3]=[CH:2]1.[Br:8][C:9]1[CH:10]=[C:11]2[C:15](=[CH:16][CH:17]=1)[NH:14][N:13]=[C:12]2[NH2:18]>C1(C)C=CC=CC=1>[Br:8][C:9]1[CH:10]=[C:11]2[C:15](=[CH:16][CH:17]=1)[NH:14][N:13]=[C:12]2[NH:18][C:1](=[O:7])[CH:2]=[CH:3][C:4]([OH:6])=[O:5]

Participants

Conditions

Temperature: 110 °C

Procedure

350 mg of maleic anhydride are added to 500 mg of 5-bromo-1H-indazole-3-amine, prepared as described in U.S. Pat. No. 3,133,081, in 20 cm3 of toluene. The medium is refluxed at about 110° C. for one hour. The heating is then stopped and the mixture is stirred at about 19° C. for 12 hours. The precipitate formed is filtered off on a sinter funnel and rinsed with 20 cm3 of diisopropyl ether, 2 cm3 of ethyl acetate and 2 cm3 of dichloromethane. After drying (90 Pa; 45° C.), 448 mg of 4-[(5-bromo-1H-indazol-3-yl)amino]-4-oxo-2-butenoic acid, Z form, are obtained in the form of a yellow solid melting at 172° C.

Workup

customprepared
customThe precipitate formed
filtrationis filtered off on a sinter funnel
washrinsed with 20 cm3 of diisopropyl ether, 2 cm3 of ethyl acetate and 2 cm3 of dichloromethane
dry with materialAfter drying (90 Pa; 45° C.), 448 mg of 4-[(5-bromo-1H-indazol-3-yl)amino]-4-oxo-2-butenoic acid, Z form

Sources & evidence

ORD record: ord-fd2fc4ae8b414aea8288fb3d3a1a1700
Source dataset: uspto-grants-2005_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06949579B2

Reaction notes

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