3-Aminopyridine → (S)-7-Nitro-3-(pyrid-3-ylimino)-1,5,10,10a-tetrahydrothiazolo[3,4-b]isoquinoline

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Reaction Steps

(S)-3-Methylthio-7-nitro-1,5,10,10a-tetrahydrothiazolo[3,4-b]isoquinolinium iodide (23 g.) is added to a solution of 3-aminopyridine (11 g.) in pyridine (400 cc.). After 6 hours at a temperature of about 20° C., the mixture is concentrated to dryness under reduced pressure (25 mm.Hg). The residue is dissolved in a mixture consisting of methylene chloride (1,500 cc.) and water (500 cc.). The organic phase is decanted, washed with water (3 × 200 cc.), dried over magnesium sulphate, filtered and then concentrated to dryness. The residue obtained is recrystallised from a mixture of acetonitrile and ethanol (1:1 by volume). (S)-7-Nitro-3-(pyrid-3-ylimino)-1,5,10,10a-tetrahydrothiazolo[3,4-b]isoquinoline (16.2 g.) is thus obtained in the form of yellow crystals melting at 234° C.

Provenance & Evidence