Ibudilast → 1-(2-Isopropyl-pyrazolo[1,5-a]pyridin-3-yl)-2-methyl-propan-1-ol

Participants

Reaction Conditions

Reaction Steps

2.5 g (10.76 mmol) of 1-(2-isopropylpyrazolo[1,5-a]pyridin-3-yl)-2-methylpropan-1-one was dissolved in MeOH (50 ml) (charcoal filtration) and cooled to 0° C. NaBH4 (570 mg, 15.06 mmol) was added portion wise. The reaction mixture was heated to reflux until complete conversion of starting material (2-4 hours). The reaction mixture was cooled to room temperature, and was quenched by the addition of water (50 ml). The aqueous layer was extracted four times with dichloromethane. The combined organic layers were washed with brine, treated with charcoal, dried over Na2SO4, and the solvent was evaporated under reduced pressure. Flash column chromatography (hexanes-ethyl acetate, 5:2; 10% deactivated silica) of the residue (yellow oil) afforded 1-(2-isopropylpyrazolo[1,5-a]pyridin-3-yl)-2-methylpropan-1-ol as a colorless oil (1.7 g, 68%), which crystallized upon trituration with pentane; m.p. 69° C. Compound 1002.

Provenance & Evidence