Formaldehyde → HCID 135453965, compound

Participants

Reaction Steps

1-(Piperidin-4-yl)-3-methyl-pyrazolo[3,4-c]isoquinolin-5(4H)-one hydrochloride (1.0 g) obtained in Example 227 and 35% aqueous formalin solution (0.53 g) were suspended in water (20 mL), and sodium triacetoxyborohydride (1.3 g) was added at room temperature, and the mixture was stirred for 1 hr. After the completion of the reaction, the solvent was evaporated, and aqueous potassium carbonate solution was added to the obtained residue. The mixture was extracted with a mixed solvent (chloroform:methanol=10:1), and the organic layer was dried over magnesium sulfate. The solvent was evaporated, and ethanol was added to the precipitated crystals. The precipitated crystals was collected by filtration and washed with ethyl acetate to give 1-(1-methylpiperidin-4-yl)-3-methyl-pyrazolo[3,4-c]isoquinolin-5(4H)-one (0.51 g) as pale-brown crystals.

Provenance & Evidence