Preparation background and overview of isoquinoline-6-boronic acid pinacol ester
Isoquinoline-6-boronic acid pinacol ester is a boric acid derivative. Boric acid derivatives are widely used in organic synthesis for the formation of carbon-carbon bonds. In the Suzuki coupling, aryl halides and aryl or vinyl borates or boronic acids are coupled using Pd(PPh3)4.
Preparation of isoquinoline-6-boronic acid pinacol ester
Preparation report of isoquinoline-6-boronic acid pinacol ester 1,
Dissolve 6-bromoisoquinoline (210 mg, 1.01 mmol) in tetrahydrofuran (10 mL), add bis-pinacol borate (305 mg, 1.20 mmol), KOAc (294 mg, 3.00 mm cyclopentopyridine ol), Pd(dppf)2Cl2 (80mg, 0.10mmol), replaced with nitrogen, refluxed overnight, cooled to room temperature, filtered with diatomaceous earth, and the filtrate was vortexed After drying, the residue was purified by column chromatography (petroleum ether: ethyl acetate = 4:1) to obtain a yellow gummy solid (270 mg, 106%).
Preparation report 2 of isoquinoline-6-boronic acid pinacol ester,
Combine 6-bromoisoquinoline (208mg, 1mmol), bis(pinacol) diborate (279mg, 1.1mmol), KOAc (323mg, 3.3mmol) and Pd(dppf)2< A mixture of Cl2 (73 mg, 0.1 mmol) in DMSO (3 mL) was heated in the microwave at 160 °C for 10 min. The mixture was diluted with water (20 mL) and extracted with EtOAc (4x 20 mL). The combined EtOAc was washed with water (15 mL) and brine (15 mL) and dried (Na2SO4). Removal of the solvent yields isoquinoline-6-boronic acid pinacol ester.
Preparation report three of isoquinoline-6-boronic acid pinacol ester
Add 20g 6-bromoquinoline, 29.2g pinacol diborate, 39.2g anhydrous potassium acetate and 2.4g PdCl2(dppf)2, add 200mL 1,4-dioxane to the reaction bottle, stir for 10 minutes, replace with nitrogen 3 times, raise the temperature to 80-95°C, the color of the system changes from dark red to black, stir at this temperature for 16 hours. Lower the temperature and filter, wash the filter cake twice with 50 mL of ethyl acetate, evaporate the filtrate to dryness, and quickly pass it through the column with 100-200 mesh silica gel to obtain 19g of quinoline-6-boronic acid pinacol ester, an off-white solid, with a yield of 95%.
References
[1] CN201610850360.X 5-fluoropyrimidine heterocyclic compounds with Wnt signaling pathway inhibitory activity and their applications
[2] CN201380021272.3 Compounds based on imidazo[1,2-b]pyridazine, compositions containing them and methods of using them
[3] [Chinese invention] CN201210257954.1 Preparation method and application of (iso)quinoline borate tetrafluoroborate tritert-butylphosphine trifluoropotassium salt
