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

HRID 1517970Notes

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 of 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 methyl 2-methyl-6-nitro-2H-indazole-3-carboxylate is obtained, which is further reacted directly in Example LIII.

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-4670b4639bd345ffa0b79e88664ca560
Source dataset: uspto-grants-2012_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08232312B2

Reaction notes

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