Synthesis
8-Quinolineboronic acid was prepared as follows: 8-Bromoquinoline (2.08 g, 10 mmol) was dissolved in 30 mL of THF, and then n-butyllithium (4 mL, 2.5 M in hexane) was added at -78 °C. After 1 hour of addition, trimethyl borate (1.23 mL, 11 mmol) was added at the same temperature. The resulting solution was stirred for 5 hours, and then 100 mL of 2 M HCl was added, followed by three extractions using 60 mL of ethyl acetate. The resulting extracts were combined, dehydrated using anhydrous magnesium sulfate, and distilled under reduced pressure. The obtained compound was separated and purified by silica gel column chromatography to produce 1.30 g (yield: 75%) of quinoline-8-boronic acid as a white solid. The obtained compound was confirmed by LC-MS.
