1-(2-Tetrahydropyranyl)-1H-pyrazole-4-boronic acid pinacol ester Chemical Properties

Melting point:

88-90°

Boiling point:

413.8±35.0 °C(Predicted)

Density 

1.16±0.1 g/cm3(Predicted)

storage temp. 

Keep in dark place,Sealed in dry,Room Temperature

form 

solid

pka

1.95±0.19(Predicted)

color 

White

InChI

InChI=1S/C14H23BN2O3/c1-13(2)14(3,4)20-15(19-13)11-9-16-17(10-11)12-7-5-6-8-18-12/h9-10,12H,5-8H2,1-4H3

InChIKey

YYSLAWXDXHVRHU-UHFFFAOYSA-N

SMILES

N1(C2OCCCC2)C=C(B2OC(C)(C)C(C)(C)O2)C=N1

Safety Information

HS Code 

2934100090

1-(2-Tetrahydropyranyl)-1H-pyrazole-4-boronic acid pinacol ester Usage And Synthesis

Uses

1-(tetrahydro-2H-pyran-2-yl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole is a useful research chemical for organic synthesis and other chemical processes.

Synthesis

The general procedure for the synthesis of 1-THP-4-pyrazoleboronic acid pinacol ester from 3,4-dihydro-2H-pyran and 4-pyrazoleboronic acid pinacol ester was as follows: 3,4-dihydro-2H-pyran (5.6 g, 67 mmol) and trifluoroacetic acid (1.17 g, 10.3 mmol) were added to a 4-(4,4,5,5-tetramethyl-1,3,2-dioxoborono pentan-2-yl)-1H-pyrazole (10.0 g, 51.5 mmol) in a solution of toluene (200 mL). The reaction mixture was heated to 90 °C and kept for 2 hours. After completion of the reaction, it was cooled to room temperature and the reaction mixture was partitioned between ethyl acetate (200 mL) and saturated aqueous sodium bicarbonate solution (100 mL). The aqueous layer was further extracted with ethyl acetate (100 mL). The organic layers were combined, washed with saturated aqueous sodium chloride (100 mL), dried over anhydrous sodium sulfate, filtered, and concentrated in vacuo. Purification by silica gel column chromatography (elution gradient: 10% to 50% petroleum ether solution of ethyl acetate) afforded the target product 1-THP-4-pyrazoleboronic acid pinacol ester as a white solid. Yield: 13.4 g, 48.2 mmol, 94% yield.1H NMR (400 MHz, CDCl3) δ 7.94 (s, 1H), 7.83 (s, 1H), 5.41 (dd, J = 9.5, 2.5 Hz, 1H), 4.01-4.08 (m, 1H), 3.65-3.74 (m, 1H), 1.98- 2.18 (m, 3H), 1.60-1.76 (m, 3H), 1.32 (s, 12H).

References

[1] Patent: WO2014/1973, 2014, A1. Location in patent: Page/Page column 60; 61; 62
[2] Patent: WO2018/201006, 2018, A1. Location in patent: Paragraph 0125; 0126
[3] Patent: WO2016/210331, 2016, A1. Location in patent: Paragraph 0225; 0226
[4] Patent: WO2016/210330, 2016, A1. Location in patent: Paragraph 0405-0406
[5] Patent: WO2009/71509, 2009, A1. Location in patent: Page/Page column 80-81