Methyl (S)-lactate (I) was converted to chloride (II) by treatment with SOCl2. Subsequent displacement in (II) by cesium thioacetate produced thioester (III). Reduction of the ester group of (III) with concomitant thioester cleavage by means of LiAlH4 in cold THF furnished mercaptoalcohol (IV).

Bromination of 2-amino-5-trifluoromethylpyridine (V) in AcOH provided bromopyridine (VI), which was submitted to a Suzuki coupling with 4-(methylthio)benzeneboronic acid (VII) yielding the phenylpyridine derivative (VIII). Oxidation of the methylthio group of (VIII) to the corresponding sulfone (IX) was carried out by treatment with N-methylmorpholine-N-oxide in the presence of OsO4. Diazotization of the amino group of (IX) generated the pyridone (X), and further chlorination employing POCl3 provided chloropyridine (XI). Finally, condensation of (XI) with (S)-2-mercaptopropanol (IV) yielded the title compound.