HCID 67282962, compound → HCID 67281623, compound

Participants

Reaction Steps

To a suspension of 3-benzyloxy-2-hydroxymethyl-1-methyl-6-(2,2,2-trifluoro-ethyl)-1H-pyridin-4-one (0.34 g, 1.04 mmol) in acetonitrile (15 mL), was added thionyl chloride (0.38 mL, 5.19 mmol) at room temperature. A clear solution resulted and the reaction was completed within 10 min. The reaction mixture was evaporated to dryness to give the crude 3-benzyloxy-2-chloromethyl-1-methyl-6-(2,2,2-trifluoro-ethyl)-1H-pyridin-4-one as an oil, which was taken up in ethanol (15 mL) to give a clear solution. Sodium borohydride (430 mg, 11.4 mmol) was added to the solution portionwise. The reaction mixture was stirred for another 10 min, and the progress of the reaction was monitored by TLC (methanol/dichloromethane, 1/10 v/v as eluant). There was still some unreacted chloride derivative present at this time. Additional sodium borohydride (360 mg, 9.5 mmol) was added in several portions. The reaction mixture was stirred for another 10 min. The reaction mixture was purified by column chromatography on silica gel (methanol/dichloromethane, 1/20 v/v as eluant) to give 3-benzyloxy-1,2-dimethyl-6-(2,2,2-trifluoro-ethyl)-1H-pyridin-4-one as an oil (0.20 g, 61% for the two combined steps, HPLC Method 1 (Example 24), RT=15.1 min, HPLC purity (peak percent area): 92% at λ=280 nm). This material, 3-benzyloxy-1,2-dimethyl-6-(2,2,2-trifluoro-ethyl)-1H-pyridin-4-one (0.20 g, 0.64 mmol) was taken up in methanol (25 mL) to give a clear solution. To the solution was added Pd/C (10 wt. %, dry basis, on activated carbon, wet, Degussa type E101 NE/W, 90 mg). The hydrogenation reaction was conducted under a hydrogen pressure of 50 psi. The reaction was completed in 30 min. A CELITE™ bed was prepared on a sintered glass, and washed with 6M HCl (100 mL), followed by water (7×50 mL) and then methanol (2×50 mL) under suction. The reaction mixture was filtered through the pre-treated CELITE™ bed. The filtrate was evaporated to give the first crop of 3-hydroxy-1,2-dimethyl-6-(2,2,2-trifluoro-ethyl)-1H-pyridin-4-one as a solid product (free base, 74 mg, 52% yield), HPLC Method 1 (Example 24), RT=9.9 min, HPLC purity (peak percent area): 96.4% at λ=280 nm). 1H NMR (DMSO-d6) δ ppm: 6.25 (s, 1H), 3.94 (q, J=11 Hz, 2H), 3.57 (s, 3H), 2.32 (s, 3H). MS-ESI (m/z) 222.2 ([M+1]+, 100%), 202.3, 153.2.

Provenance & Evidence