Water → methyl 2-methyl-6-nitro-2H-indazole-3-carboxylate

HRID 1510332Notes

Reaction equation

[N+:1]([C:4]1[CH:12]=[C:11]2[C:7](C(C(O)=O)=N[NH:10]2)=[CH:6][CH:5]=1)([O-:3])=[O:2].[C:16](=[O:19])([O-])[O-:17].[K+].[K+].[CH3:22]I.O.[CH3:25][N:26]([CH3:29])C=O>C(OCC)(=O)C>[CH3:25][N:26]1[C:29]([C:16]([O:17][CH3:22])=[O:19])=[C:7]2[C:11]([CH:12]=[C:4]([N+:1]([O-:3])=[O:2])[CH:5]=[CH:6]2)=[N:10]1

Participants

Conditions

Temperature: 50 °C

Procedure

830 mg 6-nitro-1H-indazole-3-carboxylic acid are dissolved in 16 ml dimethylformamide, combined with 1.66 g potassium carbonate and 823 μl methyl iodide and stirred for 4 hours at 50° C. After cooling to ambient temperature the mixture is divided between water and ethyl acetate. The aqueous phase is extracted twice with ethyl acetate and the combined organic phases are washed with saturated sodium chloride solution. After drying with magnesium sulphate the solvents are eliminated in vacuo. The residue is dissolved in hot dimethylformamide and after cooling to ambient temperature the precipitated solid is suction filtered and washed with diethyl ether. 670 mg of a mixture of methyl 1-methyl-6-nitro-1H-indazole-3-carboxylate and 2 methyl-methyl-6-nitro-2H-indazole-3-carboxylate is obtained, which is further reacted directly in Example IXX.

Workup

temperatureAfter cooling to ambient temperature the mixture
extractionThe aqueous phase is extracted twice with ethyl acetate
washthe combined organic phases are washed with saturated sodium chloride solution
dry with materialAfter drying with magnesium sulphate the solvents
dissolutionThe residue is dissolved in hot dimethylformamide
temperatureafter cooling to ambient temperature the precipitated solid
filtrationfiltered
washwashed with diethyl ether

Sources & evidence

ORD record: ord-f7f0c9c4ed8a46bfabb9b6be9a9966b9
Source dataset: uspto-grants-2012_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08211923B2

Reaction notes

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