4-BROMO-1-TRITYL-1H-PYRAZOLE

4-BROMO-1-TRITYL-1H-PYRAZOLE Property

Melting point:

186-188℃ (hexane )

Boiling point:

520.3±50.0 °C(Predicted)

Density 

1.27±0.1 g/cm3 (20 ºC 760 Torr)

storage temp. 

Sealed in dry,Room Temperature

pka

-0.51±0.10(Predicted)

form 

Powder

color 

White

Safety

HS Code 

2933199090

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Warning

Hazard statements

H315Causes skin irritation

H319Causes serious eye irritation

H335May cause respiratory irritation

Precautionary statements

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

P304+P340IF INHALED: Remove victim to fresh air and Keep at rest in a position comfortable for breathing.

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

P405Store locked up.

4-BROMO-1-TRITYL-1H-PYRAZOLE Chemical Properties,Usage,Production

Synthesis

To a 500 mL Schlenk flask pre-displaced with nitrogen was added 4-bromo-1H-pyrazole (10.0 g, 68.0 mmol) and anhydrous tetrahydrofuran (250 mL). After cooling the reaction system to 0°C, 60% sodium hydride dispersion (3.3 g, 81.6 mmol) was slowly added. After the hydrogen release stopped, triphenylchloromethane (20.9 g, 74.8 mmol) was slowly added and the reaction mixture was stirred at room temperature overnight. Upon completion of the reaction, the reaction was quenched with deionized water (5 mL) and subsequently dried under vacuum. The resulting residue was ground with dichloromethane (5 mL) and treated with methanol (200 mL) for 2 hours. The resulting suspension was filtered and dried at 50°C overnight to give 4-bromo-1-trityl-1H-pyrazole (26.0 g, 66.8 mmol, 98.2% yield) as a white solid. The product was characterized by 1H NMR (300 MHz, DMSO-d6) with chemical shifts of δ = 7.03-7.06 (m, 6H), 7.34-7.40 (m, 9H), 7.51 (s, 1H), 7.76 (s, 1H).

References

[1] Tetrahedron Letters, 2016, vol. 57, # 8, p. 895 - 898
[2] Patent: US2008/261975, 2008, A1. Location in patent: Page/Page column 12
[3] Journal of the American Chemical Society, 2011, vol. 133, # 31, p. 12285 - 12292
[4] Patent: US2009/82403, 2009, A1. Location in patent: Page/Page column 81
[5] Patent: US2007/105904, 2007, A1. Location in patent: Page/Page column 78