1H-INDAZOL-4-AMINE

1H-INDAZOL-4-AMINE Property

Melting point:

148-150°C

Boiling point:

376.6±15.0 °C(Predicted)

Density 

1.367±0.06 g/cm3(Predicted)

storage temp. 

under inert gas (nitrogen or Argon) at 2–8 °C

pka

15.61±0.40(Predicted)

Appearance

Light yellow to brown Solid

InChI

InChI=1S/C7H7N3/c8-6-2-1-3-7-5(6)4-9-10-7/h1-4H,8H2,(H,9,10)

InChIKey

MDELYEBAXHZXLZ-UHFFFAOYSA-N

SMILES

N1C2=C(C(N)=CC=C2)C=N1

Safety

Hazard Codes 

Xn

Risk Statements 

34-22-36/37/38

Safety Statements 

26-36/37/39-22

RIDADR 

3259

HazardClass 

IRRITANT

HS Code 

29339900

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Warning

Hazard statements

H302Harmful if swallowed

H315Causes skin irritation

H319Causes serious eye irritation

H335May cause respiratory irritation

Precautionary statements

P261Avoid breathing dust/fume/gas/mist/vapours/spray.

P305+P351+P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.

1H-INDAZOL-4-AMINE Chemical Properties,Usage,Production

Chemical Properties

Grey solid

Synthesis

The general procedure for the synthesis of 4-aminoindazole from 4-nitroindazole is as follows: 1. 2-Methyl-3-nitroaniline (2.27 g, 14.91 mmol) was dissolved in acetic acid (60 mL) and an aqueous solution of sodium nitrite (1.13 g, 1.1 eq.) was added (5 mL). After 2 hours of reaction, the dark red solution was poured into ice/water and the precipitate was collected by filtration to give 4-nitro-1H-indazole (1.98 g, 81% yield). 2. 4-Nitro-1H-indazole (760 mg, 4.68 mmol), charcoal-loaded palladium (10%, catalyst), and ethanol (30 mL) were stirred under a hydrogen balloon for 4 hours. Upon completion of the reaction, the solvent was removed in vacuum by filtration through diatomaceous earth to afford 1H-indazol-4-ylamine (631 mg, 100% yield). 3. A suspension of 1H-indazol-4-ylamine (63 mg, 4.74 mmol) in 6 M hydrochloric acid (7.2 mL) was added dropwise to an aqueous solution (2 mL) of sodium nitrite (337 mg, 4.89 mmol) at below 0 °C. After stirring for 30 min, sodium tetrafluoroborate (724 mg) was added. The reaction mixture formed a viscous solution, which was filtered and washed briefly with water to give 1H-indazole-4-diazotetrafluoroborate (218 mg, 20% yield) as a dark red solid. 4. Dry methanol (4 mL) was purged with argon for 5 min and 1H-indazole-4-diazotetrafluoroborate (218 mg, 0.94 mmol), bis(pinacolato)diboron (239 mg, 1.0 eq.), and [1,1'-bis(diphenylphosphino)ferrocene]palladium(II) chloride (20 mg) were added. The reaction mixture was stirred for 5 hours and then filtered through diatomaceous earth. The residue was purified by fast chromatography to afford the target product 4-aminoindazole (117 mg).

References

[1] Patent: WO2006/46031, 2006, A1. Location in patent: Page/Page column 31-33
[2] Patent: WO2007/42806, 2007, A1. Location in patent: Page/Page column 32-33
[3] Patent: US2008/76768, 2008, A1. Location in patent: Page/Page column 9
[4] Patent: US2008/76758, 2008, A1. Location in patent: Page/Page column 74
[5] Patent: WO2012/82997, 2012, A1. Location in patent: Page/Page column 78