Sulfuric Acid → HCID 22567058, compound

Participants

Reaction Conditions

Reaction Steps

6-Methyl-5-nitro-3-phenyl-1H-indazole can be obtained in the following way: 0.43 g of potassium nitrate is added over 5 minutes to a solution, cooled to a temperature in the region of 0° C., of 0.8 g of 6-methyl-3-phenyl-1H-indazole in 8 ml of an aqueous 98% sulfuric acid solution. The reaction mixture is stirred at a temperature in the region of 0° C. for 5 minutes and is then heated at a temperature in the region of 35-40° C. for 10 minutes and again cooled to a temperature in the region of 0° C. and stirred for 1 hour. The mixture is then poured into 50 g of ice, stirred at a temperature in the region of 0° C. for 1 hour, then filtered through sintered glass. The solid obtained is washed with 3 times 30 ml of water and partially dried and is then redissolved in 100 ml of ethyl acetate and the mixture is dried over magnesium sulfate, filtered and then concentrated to dryness under reduced pressure (2 kPa) at a temperature in the region of 40° C. The residue thus obtained is purified by chromatography on a silica column (particle size 40-63 μm), eluting successively with cyclohexane/ethyl acetate (90/10; 80/20 by volume) mixtures. The fractions containing the expected product are pooled and concentrated to dryness under reduced pressure (2 kPa) at a temperature in the region of 40° C. 0.46 g of 6-methyl-5-nitro-3-phenyl-1H-indazole is thus obtained in the form of a yellow crystalline solid melting at 164° C.

Provenance & Evidence