5-Aminoisoquinoline → (S)-3-(isoquinol-5-ylimino)-1,5,10,10a-tetrahydrothiazolo[3,4-b] isoquinoline

Participants

Reaction Conditions

Reaction Steps

5-Aminoisoquinoline (10.8 g.) is added to a solution of (S)-3-methylthio-1,5,10,10a-tetrahydrothiazolo[3,4-b]isoquinolinium iodide (18.2 g.) in pyridine (500 cc.). After 5 hours at a temperature of about 20° C., solution is complete and the reaction is allowed to continue for 10 hours. The solution is concentrated to dryness under reduced pressure (25 mm.Hg) at 60° C. The residue is dissolved in a mixture consisting of N sodium hydroxide solution (250 cc.) and methylene chloride (250 cc.). The organic phase is decanted, washed with water (2 × 100 cc.), dried over magnesium sulphate, filtered and then concentrated to dryness under reduced pressure (50 mm.Hg) at 40° C. Isopropanol (150 cc.) is added to the residue obtained; the mixture is brought to the boil and is filtered hot. After cooling to 5° C., the crystals formed and filtered off and washed with isopropanol (3 × 10 cc.). After drying at 60° C., under reduced pressure (0.1 mm.Hg), (S)-3-(isoquinol-5-ylimino)-1,5,10,10a-tetrahydrothiazolo[3,4-b] isoquinoline (13.0 g.) is obtained in the form of white crystals melting at 164° C.

Provenance & Evidence