合成路线1

The reaction of 8-methyl-8-azabicyclo[3.2.1]octan-3-one (I) with hydroxylamine and pyridine in refluxing ethanol gives the oxime (II), which is reduced with LiAlH4 in refluxing 10% H2SO4 yielding endo-methyl-8-azabicyclo[3.2.1]octan-3-amine (III). Finally, this compound is condensed with 1-isopropylbenzimidazole-2-carboxylic acid isopropyl ester (IV) by means of Al(CH3)3 in refluxing toluene. The intermediate 1-isopropylbenzimidazole-2-carboxylic acid isopropyl ester (IV) has been obtained as follows: The cyclization of o-phenylenediamine (V) with 2-hydroxyacetic acid (VI) in refluxing 4N HCl gives 1H-benzyldazole-2-ylmethanol (VII), which is oxidized with KMnO4 to the corresponding carboxylic acid (VIII). Finally, this compound is alkylated and esterified with isopropyl chloride and NaH in DMF.