preparation | 7-azaindo-4-borate ester can be prepared from 4-bromo-7-azaindole as a starting material. Isopropyl acetate (387kg) was filled into the vessel. The vessel was inerted with nitrogen and stirring was initiated. 4-bromo-7-azaindole (41.5, 211mol) was filled into the vessel. Potassium acetate (43.1, 439mol) was filled into the vessel. The vessel was filled with BIS (F-denol) diboron (54.7, 215.4mol). Bis (triphenylphosphine) palladium (II) dichloride (2.9, 4.13mol) was filled into the vessel. The contents of the vessel were heated at 85 °c to 90 °c for 22 hours. The mixture was cooled to 50 °c and then washed with water (4x 218kg). Mercapto silica (27.8) To the organic phase was added and the mixture was heated at 50 °c for 8 hours. The solid was removed by filtration and the filter cake was washed with isopropyl acetate (98kg). The combined filtrates were concentrated to a volume of approximately 240L by distillation under reduced pressure. The mixture was cooled to about 27 °c and then methyl tert-butyl ether (200kg) was added. The mixture was cooled to about 3 °c and stirred for an additional 7 hours. The solid was collected by filtration. The filter cake was washed with methyl tert-butyl ether (40kg) and then dried at approximately 40 °c to yield 7-azaindo-4-borate (39.7kg,98.9% w/w,161.0mol,76% yield). |