合成路线1

The condensation of ethyl 4-aminobenzoate (I) with 2,5-dimethoxytetrahydrofuran (II) in refluxing acetic acid/toluene gives ethyl 4-(1-pyrrolyl)benzoate (III), which by a Mannich reaction with formaldehyde and dimethylamine, followed by quaternization with methyl iodide in N,N'-dimethylimidazolidininone (DMI) yields the trimethylammonium salt (IV). The reduction of (IV) with borane/pyridine complex in DMI affords ethyl 4-(2-methyl-1-pyrrolyl)benzoate (V), which is treated with chlorosulfonyl isocyanate in heptane/toluene affording ethyl 4-(2-cyano-5-methyl-1-pyrrolyl)benzoate (VI). The reduction of (VI) with NaBH4 in methanol gives the benzyl alcohol (VII), which is treated with Ms-Cl and triethylamine to yield the mesylate (VIII). The condensation of (VIII) with N-(4-methyl-3-nitropyridin-2-yl)butyramide (IX) by means of NaOH and K2CO3 affords the disubstituted amide (X), which is cyclized by reduction of its nitro group with Fe and AcOH giving the imidazo[4,5-b]pyridine (XI). Finally, this compound is condensed with sodium azide and triethylamine in hot DMI in order to form the tetrazole ring of the target compound, which is salified with HCl in isopropanol/water.