Serinol (I) was protected with triphenylmethyl chloride giving the N-trityl derivative (II), which was O-methylated using CH3I and NaH to afford the bis(methyl ether) (III). Subsequent acid deprotection of the trityl group of (III) provided 1,3-dimethoxy-2-aminopropane (IV). The hydroxypyridone (V) was converted to the salt with cyclohexylamine (VI), and then treated with phosphoryl chloride to produce the 4-chloropyridone (VII), which was condensed with amine (IV) to yield the aminopyridone (VIII). Further treatment of (VIII) with phosphoryl chloride gave 2-chloropyridine (IX). The nitro group of (IX) was then reduced with iron powder and AcOH, and the resulting diamino pyridine (X) was treated with NaNO2 and AcOH to produce the triazolopyridine (XI). Finally, coupling of (XI) with 2-chloro-4,6-dimethylaniline (XII) in the presence of p-TsOH provided the title compound, which was isolated as the mesylate salt.