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

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Reaction Steps

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.

Provenance & Evidence