Ammonium → 1,2,3,4-Tetrahydro-7-nitroisoquinoline

Participants

Reaction Steps

1,2,3,4-Tetrahydroisoquinoline (4.0 g, 30.0 mmol) was dissolved in 10 N of sulfuric acid (6 mL, 30.0 mmol) and then evaporated to dryness to afford a solid residual. This sulfate was added slowly to a solution of potassium nitrate (3.34 g, 33.0 mmol) in sulfuric acid (15 mL), taking care that the temperature of the reaction mixture did not rise above 5° C. After being stirred at room temperature for a further 27 h, the reaction mixture was slowly poured into a con. ammonium solution (ca. 100 mL) under ice cooling. The resulted solution was extracted with dichloromethane (100 mL×3). The combined organic phase was washed with brine (150 mL), dried over Na2SO4, filtered, concentrated and purified by silica gel column chromatography (DCM:MeOH=100:1) to afford 31-2 as a brown solid (2.24 g, yield 41%).

Provenance & Evidence