Synthesis of 3,4-dihydroxy-1,8-naphthalimides with inbuilt catechol and crown ether functionalities

Abstract

Herein the synthesis of 1,8-naphthalimides functionalised as the 3,4-dihydroxy-1,8-naphthalimide (catechol, Nap-Cat) and the corresponding 15-crown-5 (Nap-Crown) is reported. These compounds represent the first examples where these two recognition groups are directly incorporated into the 1,8-naphthalimide ring system. Both Nap-Cat and Nap-Crown were evaluated for their capacity to respond to analytes such as H₂O₂ (a mimic for cellular oxidation) and metal ions (as elements of environmental and physiological interest). While slow oxidation was observed for Nap-Cat upon prolonged exposure to H₂O₂, no significant changes in photophysical properties were observed upon treatment of Nap-Crown with metal ions.