2H-Pyrazolo[3,4-c]quinolin-4-amine, 1-(2-methylpropyl)-2-propyl- → 1-(2-methylpropyl)-2-propyl-6,7,8,9-tetrahydro-2H-pyrazolo[3,4-c]quinolin-4-amine

Participants

Reaction Steps

A solution of 1-(2-methylpropyl)-2-propyl-2H-pyrazolo[3,4-c]quinolin-4-amine (0.8 g, 3 mmol), prepared as described in Example 1, in trifluoroacetic acid (10 mL) was treated with platinum (IV) oxide (0.5 g) and shaken under hydrogen pressure (50 psi, 3.4×105 Pa) for 24 hours on a Parr apparatus. The reaction mixture was diluted with chloroform (20 mL) and methanol (10 mL) and filtered through a layer of CELITE filter agent. The filtrate was concentrated under reduced pressure. The residue was suspended in 6 M aqueous hydrochloric acid (5 mL), stirred for 30 minutes, and treated with 50% aqueous sodium hydroxide to adjust the mixture to pH 13. A precipitate formed and was isolated by filtration, washed with water, and dried. The crude product was purified by chromatography on a HORIZON HPFC system (silica gel, gradient elution with 0-35% CMA in chloroform) to yield 0.55 g of 1-(2-methylpropyl)-2-propyl-6,7,8,9-tetrahydro-2H-pyrazolo[3,4-c]quinolin-4-amine as an off-white powder, mp 167-168° C.

Provenance & Evidence