Pentoxifylline → (+/-)-Lisofylline

Participants

Reaction Steps

Pentoxifylline (1.0 g, 3.59 mmol) was dissolved in methanol (20 mL) and DCM (3 mL) then cooled to 0° C. To the reaction was added sodium borohydride (0.41 g, 10.8 mmol) portionwise over 30 min. The reaction was stirred in the cold for 2 h; then it was evaporated to dryness under reduced pressure, diluted with water (100 mL) and extracted with ethyl acetate (3×75 mL). The combined extracts were dried with magnesium sulfate, filtered and the solvent was removed under reduced pressure to give 1-(5-hydroxyhexyl)-3,7-dimethyl-1H-purine-2,6(3H,7H)-dione (0.72 g, 71% yield) as a white solid. LCMS retention time=1.849 min and 98% purity, LCMS MH+ 281. 1H NMR (DMSO-d6) δ 8.00 (s, 1H), 4.31 (d, 1H, J=4 Hz), 3.88 (s, 3H), 3.84 (t, 2H, J=8 Hz), 3.51-3.59 (m, 1H), 1.45-1.56 (m, 2H), 1.25-1.37 (m, 4H), 1.02 ( d, 3H, J=4 Hz).

Provenance & Evidence