1H-INDAZOLE-4-CARBOXYLIC ACID

1H-INDAZOLE-4-CARBOXYLIC ACID Property

Melting point:

ca 280℃

Boiling point:

443.7±18.0 °C(Predicted)

Density 

1.506±0.06 g/cm3(Predicted)

storage temp. 

Sealed in dry,Room Temperature

pka

3.35±0.30(Predicted)

form 

Crystalline Powder

color 

White to cream

InChI

InChI=1S/C8H6N2O2/c11-8(12)5-2-1-3-7-6(5)4-9-10-7/h1-4H,(H,9,10)(H,11,12)

InChIKey

KGKZHHIUOZGUNP-UHFFFAOYSA-N

SMILES

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

CAS DataBase Reference

677306-38-6(CAS DataBase Reference)

Safety

Hazard Codes 

Xn

Risk Statements 

36/37/38-36-22

Safety Statements 

26-36/37/39

WGK Germany 

3

HS Code 

29339980

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Warning

Hazard statements

H302Harmful if swallowed

H319Causes serious eye irritation

Precautionary statements

P264Wash hands thoroughly after handling.

P264Wash skin thouroughly after handling.

P270Do not eat, drink or smoke when using this product.

P280Wear protective gloves/protective clothing/eye protection/face protection.

P301+P312IF SWALLOWED: call a POISON CENTER or doctor/physician IF you feel unwell.

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

P337+P313IF eye irritation persists: Get medical advice/attention.

1H-INDAZOLE-4-CARBOXYLIC ACID Chemical Properties,Usage,Production

Synthesis

The general procedure for the synthesis of indazole-4-carboxylic acid from 4-bromo-1H-indazole was as follows: sodium hydride (60% dispersed in mineral oil, 1.11 eq.) was added batchwise to an anhydrous tetrahydrofuran (7 L/mol) solution of 4-bromo-1H-indazole (1.00 eq.) at room temperature. The resulting solution was stirred at room temperature for 30 minutes and subsequently cooled to -60°C. A cyclohexane solution of 1.3 M sec-butyl lithium (2.1 eq.) was slowly added while keeping the internal temperature below -50 °C. Stirring of the reaction mixture was continued at -50 °C for 2 hours. Subsequently, a steady stream of anhydrous carbon dioxide gas was passed into the reaction mixture for 1 hour. While maintaining the carbon dioxide gas stream, the reaction mixture was allowed to gradually warm up to room temperature. Brine (6 L/mol) was added and the pH of the mixture was adjusted with concentrated hydrochloric acid to 5. The mixture was extracted with warm ethyl acetate (3 x 8 L/mol), the organic phases were combined, washed with a small amount of brine, dried over anhydrous sodium sulfate and concentrated. Finally, indazole-4-carboxylic acid was purified by silica gel column chromatography or crystallization.

References

[1] Patent: WO2004/29050, 2004, A1. Location in patent: Page 103;104