Acetic Acid → 5-Bromo-1-methyl-3-(2-methyl-1,2,3,4-tetrahydroisoquinolin-6-ylamino)pyrazin-2(1H)-one

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Reaction Steps

A mixture of 221a (2.75 g, 7.5 mmol), formaldehyde (37% in H2O, 30 mL, 375 mmol), NaBH(OAc)3 (4.75 g, 22.5 mmol), and AcOH (25 ml, 150 mmol) in methanol (125 ml) was stirred for 4 hours at room temperature. The mixture was then brought to basic condition with saturated NaOH solution and extracted with ethyl acetate. The organic layer was dried over Na2SO4 and evaporated under reduced pressure. The residue was purified by column chromatography eluting with 4:1 ethyl acetate/methanol to give 221b. (0.9 g, 34.4%) LC/MS: m/z 350 (M+H)+

Provenance & Evidence