The title urea derivative was synthesized by condensation of 6,7-dimethoxy-4-piperazinylquinazoline (I) with 4-bromophenyl isocyanate (II) in refluxing ethanol.
The condensation of 6,7-dimethoxy-4-(1-piperazinyl)quinazoline (I) with 4-bromophenylamine (II) by means of CDI or triphosgene gives the target piperazine-1-carboxamide. Alternatively, the reaction of 4-bromophenylamine (II) with 4-nitrophenyl chloroformate (III) by means of TEA gives the carbamate (IV), which is finally condensed with the quinazoline (I) in hot NMP to yield the target piperazine-1-carboxamide.
The target piperazine-1-carboxamide has been obtained by several different methods: 1.- The condensation of 6,7-dimethoxy-4-(1-piperazinyl)quinazoline (I) with 4-chlorophenyl isocyanate (II) in DMF gives the target compound. 2.- The condensation of 6,7-dimethoxy-4-(1-piperazinyl)quinazoline (I) with 4-chlorophenylamine (III) by means of CDI or triphosgene also gives the target piperazine-1-carboxamide. 3.- The reaction of 4-chlorophenylamine (III) with 4-nitrophenyl chloroformate (IV) by means of TEA gives the carbamate (V), which is finally condensed with the quinazoline (I) in hot NMP to yield the target piperazine-1-carboxamide.