1,2,3,4-Tetrahydroisoquinoline → 3,4-Dihydroisoquinoline

9.4 ml of 1,2,3,4-tetrahydroisoquinoline are dissolved in 200 ml of DCM and 14.7 g of NBS are gradually added. The mixture is left stirring at RT, cooling slightly in order to maintain a temperature of less than 40° C. for 30 minutes, after which 50 ml of 10N NaOH are added and the mixture is left stirring for 1 hour at RT. The organic phase is separated out after settling of the phases has taken place and is washed with 100 ml of water and then twice with 100 ml of 4N HCl. The aqueous phases are washed with DCM and then brought to pH=9 by addition of concentrated NH4OH. This mixture is extracted with DCM, dried over Na2SO4 and evaporated to dryness. The oil obtained is distilled off. 7.16 g of the expected compound are obtained, b.p.=50-54° C. at 0.05 mbar.

1. waitThe mixture is left
2. temperaturecooling slightly in order
3. temperatureto maintain a temperature of less than 40° C. for 30 minutes
4. waitthe mixture is left
5. stirringstirring for 1 hour at RT
6. customThe organic phase is separated out
7. washis washed with 100 ml of water
8. washThe aqueous phases are washed with DCM
9. additionbrought to pH=9 by addition of concentrated NH4OH
10. extractionThis mixture is extracted with DCM
11. dry with materialdried over Na2SO4
12. customevaporated to dryness
13. customThe oil obtained
14. distillationis distilled off

ORD record

ord-17009ae711264a15b780897882dd2b0a

Source dataset

uspto-grants-2003_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06610882B2