Lithium Hexamethyldisilazide → 1-chloro-N-(4-methoxybenzyl)-N-(pyrimidin-4-yl)isoquinoline-6-sulfonamide

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Reaction Steps

A 100-mL round-bottom flask was charged with N-(4-methoxybenzyl)pyrimidin-4-amine (Intermediate OO; 0.796 g, 3.70 mmol) and THF (16.08 ml). The flask was cooled in a dry ice-acetone bath for 10 min, then lithium bis(trimethylsilyl)amide (1M in THF) (3.70 ml, 3.70 mmol) was added drop wise. The flask was removed from the cooling bath for 5 min, then recooled for 5 min. A solution of perfluorophenyl 1-chloroisoquinoline-6-sulfonate (see EXAMPLE 73, STEP 1, 1.515 g, 3.70 mmol) in THF (4 mL with a 1-mL flask wash) was added drop wise. After 20 min, the flask was switched to an ice-water bath. The mixture was stirred for 20 min, then an additional portion of LHMDS solution (1 mL) was added drop wise. The mixture was warmed to room temperature and quenched by the addition of saturated aq. ammonium chloride. The mixture was extracted with EtOAc (2×), and the combined organic extracts were dried over sodium sulfate, filtered, and concentrated. The residue was purified by chromatography on silica gel (40-g Redi-Sep Gold column, 25-g silica gel loading column, 0-50% EtOAc/Heptante) to give 1-chloro-N-(4-methoxybenzyl)-N-(pyrimidin-4-yl)isoquinoline-6-sulfonamide (648 mg, 1.470 mmol, 39.7% yield) as a tan foam. m/z (ESI) 441.2 (M+H)+.

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