Synthesis of certain 3-aminoquinazolinone Schiff's bases structurally related to some biologically active compounds

The condensation of 2-methyl-3-amino-4(3H)-quinazolinone and 2-phenyl-3-amino-4(3H)-quinazolinone with different aldehydes is described. Reacting equimolecular amounts of these two amino compounds with p-nitrobenzaldehyde, p-hydroxybenzaldehyde, cinnamaldehyde and 5-nitro-2-furfuraldehyde diacetate afforded the respective Schiff's bases. Condensation of benzaldehyde, anisaldehyde, p-dimethylaminobenzaldehyde and o-nitrobenzaldehyde with the former quinazolinone afforded the corresponding condensation products while with the latter no condensation took place. Furthermore, condensation of cinnamaldehyde with methylaminoquinazolinone in pyridine and in glacial acetic acid afforded the mono- and di-condensation products respectively while furfural, thiophenaldehyde, resorcinaldehyde, protocatechualdehyde, veratraldehyde, and salicylaldehyde, the condensation ended in failure.