Methanesulfonic Acid → (R)-1-(5-bromopyridin-2-yl)-2-hydroxylpropan-1-one
Reaction equation
[Br:1][C:2]1[CH:3]=[CH:4][C:5]([C:8](=[O:18])[C@H:9]([O:11]C2CCCCO2)[CH3:10])=[N:6][CH:7]=1.CS(O)(=O)=O>C(O)(C)C>[Br:1][C:2]1[CH:3]=[CH:4][C:5]([C:8](=[O:18])[C@H:9]([OH:11])[CH3:10])=[N:6][CH:7]=1Participants
4
Procedure
Compound 1a (4.0 g, 12.7 mmol) was dissolved in isopropanol (50 mL), and methylsulfonic acid (1.8 g, 18.5 mmol) was added. The reaction was agitated at room temperature for 5 hrs. The reaction was monitored by TLC (petroleum ether/ethyl acetate=5/1). After the reaction completed, the solvent and excess methylsulfonic acid was removed by evaporation. The mixture was then diluted with water. The pH value was adjusted to 7-8 with saturated NaHCO3 solution. The mixture was extracted by ethyl acetate (30 mL×2). The organic phase was combined, washed with saturated sodium chloride solution, dried over anhydrous sodium sulfate, and then dried by rotary dryer. Column chromatography (petroleum ether/ethyl acetate=7/1) afforded 1.6 g of white solid (compound 1b), yield 55%.