In a 250 ml round bottomed flask equipped with a magnetic stirrer benzyl 4-((5-(3-(1-(4-amino-3-(3-fluoro-5-methoxyphenyl)-1H-pyrazolo[3,4-d]pyrimidin-1-yl)ethyl)-1-oxo-1H-isochromen-4-yl)thiophen-2-yl)methyl)piperazine-1-carboxylate (460 mg, 0.617 mmol) was suspended in 20 ml of dry dichloromethane then 1M tribromoborane in DCM (5 ml) was added and the mixture was stirred overnight at r.t. MeOH (15 ml) and 1M HCl (5 ml) were added and the mixture was stirred for 30 min then organic solvents were evaporated and the crude was purified by reverse phase chromatography eluting with H2O\MeCN\HCOOH 95:5:0.1% and MeCN\H2O\HCOOH 95:5:0.1%, to give the title compound (254 mg, 0.379 mmol, 61.4% yield) as a whitish solid.
