合成路线1

Quinazolinone (VI) was prepared by condensation of 4-chloroanthranilic acid (V) with hot formamide. Subsequent electrophilic nitration of (VI) provided the 6-nitroquinazolinone (VII) as the major regioisomer. Displacement of the 7-chloro of (VII) upon heating with ethylamine in a sealed tube gave rise to the nitro amine (VIII). The 4-chloroquinazoline derivative (IX) was then obtained by chlorination of (VIII) with phosphorus oxychloride. Condensation of (IX) with the intermediate benzylamine (IV) furnished adduct (X). The nitro group of (X) was then reduced by catalytic hydrogenation to yield the phenylenediamine derivative (XI). Finally, condensation of phenylenediamine (XI) with carbon disulfide in the presence of Et3N generated the target imidazoquinazoline, which was isolated as the dihydrochloride salt.