The condensation of 2-(chloromethyl)-4-methoxy-3-methylpyridine (I) with 5-(1-pyrrolidinyl)benzimidazole-2-thiol (II) by means of NaOH in hot methanol gives 2-(4-methoxy-3-methyl-2-pyridylmethylsulfanyl)-5-(1-pyrrolidinyl)benzimidazole (III), which is finally oxidized with m-chloroperbenzoic acid (MCPBA) in chloroform.

3-Methoxy-2-methylpyridine (VII), prepared by methylation of 2-methyl-3-pyridinol (VI), was converted to the N-oxide (VIII) employing peracetic acid. Nitration of the pyridine N-oxide (VIII) with concentrated nitric acid gave the 4-nitro derivative (IX). Subsequent displacement of the nitro group of (IX) by sodium methoxide led to the dimethoxypyridine N-oxide (X). Rearrangement of the N-oxide group of (X) in hot acetic anhydride produced the acetoxymethyl pyridine (XI). After basic hydrolysis of the acetate ester (XI), the resultant hydroxymethyl pyridine (XII) was chlorinated by SOCl2, yielding chloride (XIII). Condensation between mercapto benzimidazole (V) and the chloromethyl pyridine (XIII) in ethanolic NaOH led to the sulfide adduct (XIV). This was finally oxidized to the desired sulfoxide by using meta-chloroperbenzoic acid in CH2Cl2. The oxidation of sulfide (XIV) has also been performed employing sodium perborate, sodium percarbonate in the presence of ammonium molybdate, or tert-butyl hydroperoxide in the presence of vanadyl acetylacetonate.

The synthesis of IY-81149 can be obtained according to Scheme 22875502a. The oxidation of 2,3-lutidine (I) with hydrogen peroxide in acetic acid affords 2,3-dimethylpyridine-N-oxide (II), which is treated with sulfuric acid and nitric acid to give the corresponding nitro compound (III). The treatment of (III) with NaOH in methanol gives 2,3-dimethyl-4-methoxypyridine-N-oxide (IV), which is reacted with acetic acid and acetic anhydride and oxidized in refluxing NaOH, yielding 3-methyl-4-methoxypyridine-2-methanol (V). The chlorination of (V) with thionylchloride in CH2Cl2 affords 3-methyl-4-methoxy-2-chloromethylpyridine (VI). The reaction of 2-mercapto-5-nitrobenzimidazole (VII) with iron and concentrated HCl in refluxing ethanol and water gives monoamine (VIII), which by condensation with 2,5-dimethoxytetrahydrofuran (IX) in acetic acid yields 2-mercapto-5-(1-pyrrolyl)benzimidazole (X). The condensation of (VI) with (X) by means of NaOH in methanol gives 2-[(4-methoxy-3-methyl-2-pyridinyl)methylsulfanyl]-5-(1H-pyrrol-1-yl)-1H-benzimidazole (XI), which is finally treated with m-chloroperoxybenzoic acid (m-CPBA) in chloroform.

The synthesis of IY-81149 can be obtained according to Scheme 22875502a. The oxidation of 2,3-lutidine (I) with hydrogen peroxide in acetic acid affords 2,3-dimethylpyridine-N-oxide (II), which is treated with sulfuric acid and nitric acid to give the corresponding nitro compound (III). The treatment of (III) with NaOH in methanol gives 2,3-dimethyl-4-methoxypyridine-N-oxide (IV), which is reacted with acetic acid and acetic anhydride and oxidized in refluxing NaOH, yielding 3-methyl-4-methoxypyridine-2-methanol (V). The chlorination of (V) with thionylchloride in CH2Cl2 affords 3-methyl-4-methoxy-2-chloromethylpyridine (VI). The reaction of 2-mercapto-5-nitrobenzimidazole (VII) with iron and concentrated HCl in refluxing ethanol and water gives monoamine (VIII), which by condensation with 2,5-dimethoxytetrahydrofuran (IX) in acetic acid yields 2-mercapto-5-(1-pyrrolyl)benzimidazole (X). The condensation of (VI) with (X) by means of NaOH in methanol gives 2-[(4-methoxy-3-methyl-2-pyridinyl)methylsulfanyl]-5-(1H-pyrrol-1-yl)-1H-benzimidazole (XI), which is finally treated with m-chloroperoxybenzoic acid (m-CPBA) in chloroform.