Isatoic Anhydride: A Fascinating and Basic Molecule for the Synthesis of Substituted Quinazolinones and Benzo di/triazepines

This review article is focused on the synthesis of compounds with quinazolinones and benzo di/triazepine scaffolds. These invaluable derivatives are of great interest in medicinal and pharmaceutical studies because of their important biological properties. Quinazolinones have diverse applications due to their antibacterial, analgesic, antiinflammatory, antifungal, antimalarial, antihypertensive, CNS depressant, anticonvulsant, antihistaminic, antiparkinsonism, antiviraland and anticancer activities. On the other hand, pharmacological properties of benzodiazepines include antianxiety, anticancer, anticonvulsant, antagonists of cholecystokinin receptors (CCK), antileishmanial, sleep-inducing muscle relaxant and several other useful and interesting properties. As an example, three main categories of drugs, namely anxiolytics, sedative hypnotics (sleep inducers) and anticonvulsants are constructed by 1,4-benzodiazepines. Finally, benzotriazepines are believed to possess various pharmacological properties such as antipsychotic and antitumor activities. Hence, this review is divided into three major sections, considering quinazolinones, benzodiazepines and benzotriazepines. In the first section, we take a brief look at various approaches towards synthesis of substituted quinazolin-4(3H)-ones and 2,3-dihydroquinazolin-4(1H)-ones. Also in this section, we try to give an overview of the synthetic routes and strategies recently reported for the generation of various classes of substituted 4(3H)-quinazolinones and 2,3-dihydroquinazolin-4(1H)-ones. Accordingly, quinazolin-4(3H)-ones, were subdivided into three major classes: 2-substituted, 3-substituted and 2,3-disubstituted-quinazolinones. 2,3- dihydroquinazolin-4(1H)-ones also were subdivided into six sub-categories: 2-monosubstituted, 2,2- disubstituted, 2,3-disubstituted, 1,2,3-trisubstituted, 2,2,3-trisubstituted 2,3-dihydroquinazolin-4(1H)-ones and boron-containing quinazoline-4(1H)-ones. In the other two sections, we cover the literature related to synthesis of benzo di/triazepine. The most recent developments are highlighted with a special emphasis on new synthetic routes based on isatoic anhydride as starting material.