Methyl iodide → (4R)-4,5-Dihydro-2-(methylthio)-4-thiazolemethanol

To a mixture solution of 4.88 g of 4(R)-hydroxymethyl-2-mercapto-1,3-thiazoline [Compound (5)] and 22.8 ml of diisopropylethylamine in 65 ml of dry methanol was added 14.00 g of methyl iodide under refluxing condition, and the reaction mixture was refluxed for 1 hour. After removal of the solvent under reduced pressure, the resulting residue was dissolved in ethyl acetate and the organic layer was washed with saturated sodium bicarbonate solution, water and saturated saline solution and dried over magnesium sulfate. The solvent was removed under reduced pressure and the resulting residue was purified by silica gel column chromatography (chloroform-acetone) to give 3.14 g (59%) of 4(R)-hydroxymethyl-2-methylthio-1,3-thiazoline [Compound (6)].