4-AMINO-6-BROMO (1H)INDAZOLE

4-Nitro-1H-indazole 9a (commercially available, CAS: 2942-40-7, 1.4 g, 8.26 mmol) or 6-bromo-4-nitro-1H-indazole 9b (commercially available, CAS: 885518-46-7, 2.0 g, 8.26 mmol) was taken in a round bottom flask having ethanol (20 mL) and water (10 mL) as solvents. Ammonium chloride (221.5 mg, 4.13 mmol) was added and the solution was stirred for 5 min at ambient temperature. To this content, a portion of iron powder (1.3 g, 23.46 mmol) was added slowly and stirred for 5 min at 80 C. Then another portion of iron powder (1.0 g, 17.86 mmol) was added and the stirring was continued at 80 C for 20 min. The mixture was immediately filtrated and the filter residue was washed with ethanol (10 mL). The filtrate was concentrated under reduced pressure and then dissolved in ethyl acetate (8 mL). The organics were washed with brine, dried with anhydrous Na2SO4 and concentrated. The solid produced was purified through the column chromatography on silica gel with petroleum ether and ethyl acetate (8:1) as eluent to afford 10a (379.0 mg, 93percent) or 10b (1.62 g, 92percent) as a yellow solid.The nitro compound (8.26 mmol) was dissolved in a mixed solvent of ethanol (20 mL) and water (10 mL), ammonium chloride (221.5 mg, 4.13 mmol) was added, and a portion of the iron powder was first (1.3 g, 23.46 mmol). ) was added thereto, and the temperature was raised to 80 °C. The reaction was stirred for 5 minutes, and the remaining iron powder (1.0 g, 17.86 mmol) was added, and the reaction was further stirred for 20 minutes. After the reaction was completed by TLC, the reaction solution was filtered while hot, and the filter residue was washed with ethanol (10 mL). The ethanol was removed under reduced pressure and the aqueous layer was extracted three times with ethyl acetate (20 mL). The organic phases were combined, washed with saturated brine, dried over anhydrous magnesium sulfate, and spin-dried and passed through a column (PE: oxime = 8:1) to give the corresponding amino compound.Compound 7a (8.26 mmol) was dissolved in a mixed solvent of ethanol (20 mL) and water (10 mL).Ammonium chloride (221.5 mg, 4.13 mmol) was added, and a part of iron powder (1.3 g, 23.46 mmol) was added thereto, and the mixture was heated to 80 ° C and stirred for 5 minutes.The remaining iron powder (1.0 g, 17.86 mmol) was added and the reaction was stirred for 20 minutes.After the TLC was used to detect the completion of the reaction, the reaction solution was filtered while hot, and the residue was washed with ethanol (10 mL).Ethanol was evaporated under reduced pressure and the aqueous layer was extracted with ethyl acetate (20mL).The organic phase was combined, washed with brine, dried over anhydrous magnesium sulfate, and dried, and then passed to the column (PE: EA = 8:1) to give 6-bromo-1H-indazole-4-amine.

Molecular Weight:212.05
XLogP3:1.6
Hydrogen Bond Donor Count:2
Hydrogen Bond Acceptor Count:2
Exact Mass:210.97451
Monoisotopic Mass:210.97451
Topological Polar Surface Area:54.7
Heavy Atom Count:11
Complexity:153
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes