[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]1830 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.
Wird geladen…
