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

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%).

1. customevaporated to dryness
2. customto afford a solid residual
3. customdid not rise above 5° C
4. additionthe reaction mixture was slowly poured into a con
5. extractionThe resulted solution was extracted with dichloromethane (100 mL×3)
6. washThe combined organic phase was washed with brine (150 mL)
7. dry with materialdried over Na2SO4
8. filtrationfiltered
9. concentrationconcentrated
10. custompurified by silica gel column chromatography (DCM:MeOH=100:1)

ORD record

ord-20263df529cb4e6b85657f0d13c9a538

Source dataset

uspto-grants-2014_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08691816B2