Synthesis of 2-salicylidenaminophenyl substituted quinazolin-4(3H)-ones as potential fluorescent probes

2-(Salicylidenaminophenyl)-substituted quinazolin-4(3H) ones were synthesized in two steps from 2-(4-nitrophenyl)- or 2-(3-nitrophenyl)quinazolin-4(3H)-ones. The synthesized compounds exhibit tunable absorption (340–404 nm) and weak emission in THF at 420–600 nm. The meta-isomers show hypsochromically shifted bands relative to the para analogues, while selected derivatives exhibit a fluorescence ‘turn-on’ response toward Al³⁺ ions.