2-Ethyl-5-nitroaniline → 3-Methyl-6-nitro-1H-indazole
Reaction equation
[CH2:1]([C:3]1[CH:9]=[CH:8][C:7]([N+:10]([O-:12])=[O:11])=[CH:6][C:4]=1[NH2:5])[CH3:2].[N:13]([O-])=O.[Na+]>C(O)(=O)C.O>[CH3:2][C:1]1[C:3]2[C:4](=[CH:6][C:7]([N+:10]([O-:12])=[O:11])=[CH:8][CH:9]=2)[NH:5][N:13]=1Participants
Reactant 2
Product 1
Reagents, catalysts & solvents 2
Conditions
- Temperature
- 0 °C
Procedure
Following generally the procedure reported by Organic Synthesis 1955, Coll. Vol. 3, 660; 1940, 20, 73, 2-ethyl-5-nitroaniline (1.021 g, 6.14 mmol) was dissolved in glacial acetic acid (40 ml) and the mixture was cooled to 0° C. A solution of sodium nitrite (1 eq, 424 mg) in water (1 ml) was added all at once. Stirring was continued for 15 minutes at 25° C. After 3 hours, residual solids were filtered off and discarded, and the filtrate was allowed to stand for 3 days at room temperature. The solution was concentrate in vacuo, and the residue was diluted with 2 ml of water and stirred vigorously. The solid product was filtered and washed thoroughly with cold water, dried and purified by flash chromatography (4:1 hexanes/ethyl acetate) to give 3-methyl-6-nitro-1H-indazole (436 mg, 40.5%) as a solid.
Workup
- customreported by Organic Synthesis 1955, Coll
- waitAfter 3 hours
- filtrationresidual solids were filtered off
- waitto stand for 3 days at room temperature
- concentrationThe solution was concentrate in vacuo
- additionthe residue was diluted with 2 ml of water
- stirringstirred vigorously
- filtrationThe solid product was filtered
- washwashed thoroughly with cold water
- customdried
- custompurified by flash chromatography (4:1 hexanes/ethyl acetate)
Sources & evidence
- ORD record
- ord-3766ee020f2c45baa668d02755a6bc94
- Source dataset
- uspto-grants-2012_04
- Patent number
- US08153809B2
Reaction notes
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