1-Benzyl-1H-pyrazole-4-boronic acid pinacol ester Chemical Properties

Melting point:

86-90 °C(lit.)

Boiling point:

427.9±28.0 °C(Predicted)

Density 

1.07±0.1 g/cm3(Predicted)

storage temp. 

Keep in dark place,Sealed in dry,Room Temperature

solubility 

soluble in Methanol

pka

1.85±0.10(Predicted)

form 

solid

color 

white to yellow

Water Solubility 

Insoluble

InChIKey

ZVPORPUUZXIPEF-UHFFFAOYSA-N

CAS DataBase Reference

761446-45-1(CAS DataBase Reference)

Safety Information

Hazard Codes 

Xi

Risk Statements 

36/37/38-23-22

Safety Statements 

22-24/25-37/39-26-36/37/38

WGK Germany 

3

Hazard Note 

Irritant

TSCA 

No

HS Code 

29331990

MSDS

• Language:English Provider:SigmaAldrich
• Language:English Provider:ACROS

1-Benzyl-1H-pyrazole-4-boronic acid pinacol ester Usage And Synthesis

Chemical Properties

off-white to light yellow crystals or

Uses

1-Benzylpyrazole-4-boronic acid pinacol ester can be used:

• As a model compound in the study of the stability of boronate esters in different alcohols using the LCMS technique.
• As a substrate in the study of palladium-catalyzed methylation of heteroaryl boronate esters using iodomethane.
• As a substrate in the preparation of bromodifluoromethylthiolated arenes, applicable in the radiosynthesis of [¹⁸F]ArylSCF₃ compounds.

Synthesis

GENERAL STEPS: 4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-1H-pyrazole (3.0 g, 15.5 mmol) was mixed with bromomethylbenzene (3.2 g, 18.7 mmol) in a solution of DMF (30 mL) containing K2CO3 (4.3 g, 31.2 mmol) and stirred at room temperature overnight. After completion of the reaction, the reaction mixture was diluted with EtOAc (50 mL) and H2O (50 mL), the organic layer was separated and washed with brine (50 mL). The organic layer was dried over Na2SO4, filtered and concentrated in vacuum. The residue was purified by silica gel column chromatography using PE/EtOAc (5:1) as eluent to afford the target compound 1-benzyl-4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-1H-pyrazole (3.5 g, 12.3 mmol) as a light yellow solid in 79% yield.1H NMR (400 MHz. CDCl3): δ 7.81 (s, 1H), 7.66 (s, 1H), 7.37-7.29 (m, 3H), 7.24-7.22 (m, 2H), 5.30 (s, 2H), 1.29 (s, 12H). lcms (M + H) + 285.

References

[1] Patent: US2018/296543, 2018, A1. Location in patent: Paragraph 0573; 0574; 0600
[2] Patent: WO2015/95767, 2015, A1. Location in patent: Page/Page column 284; 285
[3] Patent: WO2016/124508, 2016, A1. Location in patent: Page/Page column 55
[4] Journal of Medicinal Chemistry, 2016, vol. 59, # 4, p. 1370 - 1387
[5] Patent: WO2014/60395, 2014, A1. Location in patent: Page/Page column 35

1-Benzyl-1H-pyrazole-4-boronic acid pinacol ester(761446-45-1)Related Product Information

• Benzyl benzoate
• Benzyltrimethylammonium chloride
• Benzyl butyrate
• Benzyl bromide
• Benzyl chloride
• Pinacol
• Benzyl acetate
• Benzyl alcohol
• Benzoyl peroxide
• Pyrazole
• N,N-Dimethylbenzylamine
• Benzylboronic acid
• 2,2,4-Trimethyl-1,3-pentanediol monoisobutyrate
• Benzyltriethylammonium chloride
• DIBENZYLTOLUENE
• Phenylacetone
• 1-Methyl-4-pyrazole boronic acid pinacol ester
• Benzyl