Reaction of 3-fluoroaniline (I) with benzyl chloroformate provides carbamate (II). The lithium derivative of (II) is then condensed with (R)-glycidyl butyrate (III) to yield the chiral oxazolidinone (IV). After conversion of alcohol (IV) to the corresponding mesylate (V), displacement with NaN3 in hot DMF gives rise to the alkyl azide (VI). Catalytic hydrogenation of azide (VI) furnishes amine (VII), which is further acylated with acetic anhydride, producing acetamide (VIII). Aromatic iodination of (VIII) by means of iodine monochloride in the presence of trifluoroacetic acid gives (IX). Iodide compound (IX) is then converted into the aryl stannane (X) upon treatment with hexamethyl ditin and palladium catalyst
Treatment of 2,5-dibromopyridine (XI) with NaCN/CuCN gives rise to nitrile (XII). Cycloaddition of NaN3 to the cyano group of (XII) then leads to the tetrazolyl pyridine (XIII) (1). Further methylation of tetrazole (XIII) with iodomethane and KOH produces a mixture of methylated regioisomers (XIV) and (XV). The desired 2-methyl tetrazole derivative (XIV) is finally subjected to Stille coupling with the aryl stannane (X) to furnish the title compound