Sodium cyanoborohydride → 1,2,3,5,6,10b-Hexahydropyrrolo[2,1-a]isoquinoline

Participants

Reaction Steps

To a solution of 2,3,5,6-tetrahydro-1H-pyrrolo[2,1-a]isoquinolinium chloride (prepared by the method of S. Akaboshi, T. Kutsuma, and K. Achiwa, J. Pharm. Bull., 1960, 8, 14, from N-(2-phenylethyl)-4-chlorobutyramide (56.4 g, 0.25 mol) and extracted into isopropanol-dichloromethane) in methanol (700 ml) and acetic acid (50 ml) at 0° C. was added portionwise sodium cyanoborohydride (19 g) over 1 h. After stirring overnight, the solvent was concentrated in vacuo. The residue was dissolved in dilute sodium hydroxide and was extracted twice with dichloromethane. The dried (magnesium sulfate) organic phase was concentrated to give an oil which was distilled using a Kugelrohr distilling apparatus, b.p. 100° C. at 0.25 mm, to give the title compound (30.4 g, 70%) as a pale yellow oil.

Provenance & Evidence