3-BROMO-1H-PYRAZOLE Chemical Properties

Melting point:

60-65°C

Boiling point:

70-72 °C(Press: 0.1 Torr)

Density 

1.904±0.06 g/cm3(Predicted)

storage temp. 

-20°C

form 

crystals

pka

10.88±0.10(Predicted)

color 

White-pale yellow

InChI

InChI=1S/C3H3BrN2/c4-3-1-2-5-6-3/h1-2H,(H,5,6)

InChIKey

XHZWFUVEKDDQPF-UHFFFAOYSA-N

SMILES

N1C=CC(Br)=N1

CAS DataBase Reference

14521-80-3

Safety Information

Hazard Codes 

Xn

Risk Statements 

22-36/37/38

Safety Statements 

26-37/39

WGK Germany 

1

HS Code 

2933119000

3-BROMO-1H-PYRAZOLE Usage And Synthesis

Uses

3-Bromopyrazole is a useful synthetic intermediate in the synthesis of Rynaxypyr (C325380); an insecticidal anthranilic diamide that acts as a potent and selective ryanodine receptor activator.

Synthesis

General procedure for the synthesis of 3-bromopyrazole from 1-(dimethylaminosulfonyl)-3-bromopyrazole: 3-bromo-N,N-dimethyl-1H-pyrazole-1-sulfonamide (5.83 g) obtained in step B was mixed with trifluoroacetic acid (9.0 mL) and the reaction was stirred for 2 hours at room temperature. Upon completion of the reaction, ethyl acetate was added to the mixture, followed by neutralization of the reaction solution with saturated aqueous sodium bicarbonate and washing with saturated aqueous sodium chloride. The organic layer was separated, dried with anhydrous sodium sulfate and concentrated under reduced pressure to remove the solvent. The resulting crude product was purified by silica gel column chromatography (eluent: ethyl acetate/hexane) to give the final target compound 3-bromopyrazole (2.92 g). The product was characterized by 1H NMR (400 MHz, CDCl3): δ 6.37 (1H, d, J=2.4 Hz), 7.57 (1H, d, J=2.4 Hz).

References

[1] Patent: WO2006/68669, 2006, A1. Location in patent: Page/Page column 19; 24
[2] Patent: WO2003/106427, 2003, A2. Location in patent: Page 18
[3] Patent: WO2004/11447, 2004, A2. Location in patent: Page 42-43
[4] Patent: EP2818473, 2014, A1. Location in patent: Paragraph 0583
[5] Patent: US9113630, 2015, B2. Location in patent: Page/Page column 41; 42

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