The esterification of 3-nitroquinoline-2,4-diol (I) with trifluoromethanesulfonic anhydride (II) gives the disulfonate (III), which is condensed with 2-hydroxyisobutylamine (IV) and triethylamine in dichloromethane, yielding the aminoquinoline (V). The reaction of (V) with dibenzylamine by means of triethylamine in refluxing toluene affords the quinolinediamine (VI), which by reduction of its nitro group with NaBH4 provides the quinolinetriamine (VII). The cyclization of (VII) with 2-ethoxyacetyl chloride (VIII) by means of p-toluenesulfonic acid in refluxing acetonitrile gives the protected imidazoquinoline (IX), which is finally deprotected by treatment with Pd/C and formic acid.

The cyclization of the diaminoquinoline (I) with ethoxyacetic acid (II) by heating at 120 C gives the imidazoquinoline (III), which is oxidized to the 5-N-oxide (IV) by treatment with peracetic acid. Finally, compound (IV) is aminated by means of ammonium hydroxide and p-toluenesulfonyl chloride in dichloromethane.

The esterification of 3-nitroquinoline-2,4-diol (I) with trifluoromethanesulfonic anhydride (II) gives the disulfonate (III), which is condensed with 2-hydroxyisobutylamine (IV) and triethylamine in dichloromethane, yielding the aminoquinoline (V). The reaction of (V) with dibenzylamine by means of triethylamine in refluxing toluene affords the quinolinediamine (VI), which by reduction of its nitro group with NaBH4 provides the quinolinetriamine (VII). The cyclization of (VII) with 2-ethoxyacetyl chloride (VIII) by means of p-toluenesulfonic acid in refluxing acetonitrile gives the protected imidazoquinoline (IX), which is finally deprotected by treatment with Pd/C and formic acid.

The cyclization of the diaminoquinoline (I) with ethoxyacetic acid (II) by heating at 120 C gives the imidazoquinoline (III), which is oxidized to the 5-N-oxide (IV) by treatment with peracetic acid. Finally, compound (IV) is aminated by means of ammonium hydroxide and p-toluenesulfonyl chloride in dichloromethane.