5-Amino-3-methoxymethylisoquinoline → (S)-3-[(3-Methoxymethylisoquinol-5-yl)imino]-1,5,10,10a-tetrahydrothiazolo[3,4-b]isoquinoline

Participants

Reaction Steps

(S)-3-Methylthio-1,5,10,10a-tetrahydrothiazolo[3,4-b]isoquinolinium iodide (13.0 g) is added to a solution of 5-amino-3-methoxymethylisoquinoline (6.8 g) in pyridine (200 cc). After 18 hours at a temperature of about 20° C., the mixture is concentrated to dryness under reduced pressure (25 mm Hg; 3.3 kPa). The residue is dissolved in a mixture of 4 N sodium hydroxide solution (100 cc) and methylene chloride (200 cc). The organic phase is decanted, washed with water (100 cc), dried over magnesium sulphate and filtered, and the filtrate is then concentrated to dryness under reduced pressure (20 mm Hg; 2.7 kPa) at 40° C. The residue is crystallized by trituration with diisopropyl ether (50 cc) and then recrystallised from ethanol (200 cc). (S)-3-[(3-Methoxymethylisoquinol-5-yl)imino]-1,5,10,10a-tetrahydrothiazolo[3,4-b]isoquinoline (11.3 g) is thus obtained in the form of light beige crystals melting at 134° C.

Provenance & Evidence