4-Hydroxy-6-methyl-3-nitro-2-pyridone (I) was treated with phosphoryl chloride in boiling N,N-diethylaniline, and the resulting dichloropyridine (II) was condensed with n-butyl ethylamine (III) to afford a regioisomeric mixture of 4- (IV) and 2-amino (V) pyridines. After chromatographic separation, the desired isomer (IV) was coupled with 2-bromo-4-isopropylaniline (VI) at 140 C to provide (VII). Reduction of the nitro group of (VII) using sodium hydrosulfite and ammonia yielded diamine (VIII). Subsequent cyclization of (VIII) with phosgene in refluxing toluene gave imidazopyridinone (IX), which was finally N-methylated by means of CH3I and KOH in acetone.