* All experimental methods are cited from the reference, please refer to the original source for details. We do not guarantee the accuracy of the content in the reference.
With sodium hydroxide; boron tribromide; In (2S)-N-methyl-1-phenylpropan-2-amine hydrate; dichloromethane;
III. Synthesis of 7-Hydroxyisoquinoline To a 2-liter, 3-necked round bottom flask equipped with a magnetic stir bar and addition funnel is added 19.7 g (0.124 mole) <strong>[39989-39-4]7-methoxyisoquinoline</strong> and 800 ml of dry dichloromethane. This solution is stirred and cooled to -75 C. with a dry ice/acetone bath, 628 ml (0.628 mole) of 1.0M boron tribromide in dichloromethane is added dropwise maintaining the temperature at -75 C. Thereafter the slurry is stirred for 18 hours allowing the temperature to rise to room temperature. The reaction slurry is poured into 1 liter of ice water and stirred for an hour. The layers are separated and the aqueous layer is then adjusted from acidic to neutral (pH 7) with 1N NaOH. A yellow solid precipitates and is filtered off, then air dried to yield 14.5 g of a yellow solid, 81%.
With pyridine hydrochloride; In ethyl acetate;
(15-1) The raw material <strong>[39989-39-4]7-methoxyisoquinoline</strong> was prepared according to J. Org. Chem., 38(21), 3701(1973). A mixture of 7.4 g of <strong>[39989-39-4]7-methoxyisoquinoline</strong> and 30 g of pyridine hydrochloride was heated with stirring at 180 for 6 hours. The reaction mixture was allowed to cool, dissolved in ethyl acetate, and washed with a saturated aqueous sodium chloride solution. The solution was dried with anhydrous magnesium sulfate and the solvent was distilled off under reduced pressure to give 4.43 g of 7-hydroxyisoquinoline.
IV. Synthesis of 7-Hydroxy-8-nitroisoquinoline To a 300 ml round bottom flask is added 14.5 g (0.1 mole) of 7-hydroxyisoquinoline and 100 ml of warmed tetramethylene sulfone. The brown slurry is stirred and to it is added portionwise 18.6 g (0.14 mole) of nitronium tetrafluoroborate with cooling (ice bath). The reaction is stirred for 3 hours. The reaction is then quenched with 100 ml of methanol, evaporated to dryness and triturated twice with ether to precipitate a dark solid (19.0 g, 100%).
100%
With nitronium tetrafluoroborate; In methanol;
IV. Synthesis of 7-Hydroxy-8-nitroisoquinoline To a 300 ml round bottom flask is added 14.5 g (0.1 mole) of 7-hydroxyisoquinoline and 100 ml of warmed tetramethylene sulfone. The brown slurry is stirred and to it is added portionwise 18.6 g (0.14 mole) of nitronium tetrafluoroborate with cooling (ice bath). The reaction is stirred for 3 hours. The reaction is then quenched with 100 ml of methanol, evaporated to dryness and triturated twice with ether to precipitate a dark solid (19.0 g, 100%).
With sodium hydroxide; boron tribromide; In (2S)-N-methyl-1-phenylpropan-2-amine hydrate; dichloromethane;
III. Synthesis of 7-Hydroxyisoquinoline To a 2-liter, 3-necked round bottom flask equipped with a magnetic stir bar and addition funnel is added 19.7 g (0.124 mole) of <strong>[39989-39-4]7-methoxyisoquinoline</strong> and 800 ml of dry dichloromethane. This solution is stirred and cooled to -75 C. with a dry ice/acetone bath, 628 ml (0.628 mole) of 1.0M boron tribromide in dichloromethane is added dropwise maintaining the temperature at -75 C. Thereafter the slurry is stirred for 18 hours allowing the temperature to rise to room temperature. The reaction slurry is poured into 1 liter of ice water and stirred for an hour. The layers are separated and the aqueous layer is then adjusted from acidic to neutral (pH 7) with 1N NaOH. A yellow solid precipitates and is filtered off, then air dried to yield 14.5 g of a yellow solid, 81%.