HCID 70416117, compound → HCID 70416551, compound

Participants

Reaction Steps

Cis-1,3,4,6,7,11b-hexahydro-9-methoxy-2-methyl-6-methyl-2H-pyrazino[2,1-a]isoquinoline-3,4-dione (16.0 g, 0.04 mol) was added with stirring to a solution of 1M borane in tetrahydrofuran (350 ml) under nitrogen and the resulting mixture was refluxed for 4 hrs, then cooled to 0° C., and then treated with 10% HCl (150 ml). The mixture was refluxed for 1 hr and cooled, and then the solvent was evaporated. The aqueous residue was basified to pH 11 with 50% NaOH and extracted with chloroform (3×250 ml). The combined chloroform extracts were dried over MgSO4 and evaporated to an oily residue. The residue was dissolved in methanol/isopropanol (150 ml) and acidified with HCl gas. A solid salt crystallized (10.3 g) which was recrystallized from methanol (300 ml) and water (10 ml) to give 9.8 g of cis-1,3,4,6,7,11b-hexahydro-9-methoxy-2-methyl-2H-pyrazino[2,1-a]isoquinoline dihydrochloride as an off-white solid. An analytical sample had mp. 274°-275° C. Following the same procedure and substituting trans-1,3,4,6,7,11b-hexahydro-9-methoxy-2-methyl-6-phenyl-2H-pyrazino[2,1-a]isoquinoline-3,4-dione for cis-1,3,4,6,7,11b-hexahydro-9-methoxy-2-methyl-6-phenyl-2H-pyrazino[2,1-a]isoquinoline-3,4-dione, trans-1,3,4,6,7,11b-hexahydro-9-methoxy-2-methyl-6-phenyl-2H-pyrazino[2,1-a]isoquinoline dihydrochloride may be obtained.

Provenance & Evidence