[N+:1]([C:4]1[CH:12]=[CH:11][CH:10]=[C:9]2[C:5]=1[CH:6]=[N:7][NH:8]2)([O-:3])=[O:2].CI.[C:15](=O)([O-])[O-].[Cs+].[Cs+].O>CN(C=O)C>[CH3:15][N:8]1[C:9]2[C:5](=[C:4]([N+:1]([O-:3])=[O:2])[CH:12]=[CH:11][CH:10]=2)[CH:6]=[N:7]16.5 g of 4-nitroindazole (Chem. Ber. (1904), 37, 2583), 1.9 ml of methyl iodide and 14.4 g of cesium carbonate in 110 ml of DMF are stirred for 2 hours at 0° C. and then for 12 hours at room temperature. It is added to water and extracted with ethyl acetate. The organic phase is washed with water and brine, dried (Na2SO4) and concentrated by evaporation. The residue is recrystallized from ethyl acetate/hexane. 2.49 g of 1-methyl-4-nitroindazole is obtained. The latter is hydrogenated in 70 ml of THF with 420 mg of palladium on activated carbon under normal pressure with hydrogen. The batch is filtered through diatomaceous earth and completely concentrated by evaporation. 2.1 g of the title compound is obtained.
Wird geladen…
