1-Boc-7-Azaindole-3-boronic acid pinacol ester Chemical Properties

Melting point:

115-117 °C

Boiling point:

460.9±48.0 °C(Predicted)

Density 

1.13±0.1 g/cm3(Predicted)

storage temp. 

Inert atmosphere,Store in freezer, under -20°C

pka

2.68±0.30(Predicted)

Appearance

White to off-white Solid

Safety Information

HS Code 

2933998090

1-Boc-7-Azaindole-3-boronic acid pinacol ester Usage And Synthesis

Synthesis

1-Boc-3-iodo-7-azaindole (7.5 g, 0.022 mol) was used as a starting material and reacted with bis(pinacolato)diboron (16.6 g, 0.065 mol), potassium acetate (12.8 g, 0.13 mol), and [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) dichloromethane complex (1.78 g, 0.002 mol) was mixed in 80 mL of N,N-dimethylformamide and reacted at 90 °C for 3 hours. After completion of the reaction, the solvent was removed by rotary evaporation and the residue was dissolved in dichloromethane and purified by ISCO column chromatography with the eluent being a hexane solution of 15-25% ethyl acetate to give the target product (10% yield). Mass spectrum (ES+) m/z = 345 (M + 1). Also taken were tert-butyl 3-iodo-pyrrolo[2,3-b]pyridine-1-carboxylate (490 mg, 0.00142 mol), bis(pinacolato)diboron (1.11 g, 0.00436 mol), potassium acetate (0.86 g, 0.0087 mol) and [1,1'-bis(diphenylphosphino)ferrocene]palladium(II) dichloride dichloromethane complex ( 0.117 g, 0.000143 mol) was dissolved in N,N-dimethylformamide (8 mL) in a sealed tube and reacted at 80 °C for 2.5 hours. After the reaction, the solvent was removed by evaporation and purified by silica gel column chromatography to afford tert-butyl 3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrrolo[2,3-b]pyridine-1-carboxylate (234 mg, 48% yield). Mass spectrum m/z = 345.24 (M + 1).1H NMR (300 MHz, CDCl3) δ 8.478 (dd, J = 4.6, 1.5 Hz, 1H), 8.234 (dd, J = 7.7, 1.7 Hz, 1H), 8.031 (s, 1H), 7.191 (dd, J = 7.9, 4.8 Hz, 1H), 1.644 (s, 9H), 1.352 (s, 12H).TLC Rf = 0.43 (Expander: 3:1 hexane/ethyl acetate).

References

[1] Patent: WO2008/5457, 2008, A2. Location in patent: Page/Page column 101; 109