Novel synthesis of known carcinogen precursors

5-Amino-1-methylbenzimidazole (2) prepared from 2,4-dinitrochlorobenzene in four steps is a suitable reagent for nucleophilic vinylic substitution with various enolethers (3) thus affording N-substituted enaminoesters — aminoethylene derivatives (4). Their thermal cyclocondensation reaction under the Gould-Jacobs protocol gives regioselectively angularly annelated 8-substituted imidazo[4,5-f]quinolones (5), whose mechanism of origin has been attempted. The obtained results give suitable structures for the synthesis of food-borne carcinogen IQ (1).