The heterocyclic compounds have a great importance in medicinal chemistry. One of the most important heterocycles in medicinal chemistry are quinazolines possessing wide spectrum of biological properties like antibacterial, antifungal, anticonvulsant, anti-inflammatory, anti-HIV, anticancer and analgesic activities. This skeleton is an important pharmacophore considered as a privileged structure. This review highlights the recent advances in the synthesis of quinazolines and quinazolinone derivatives with potent antimicrobial and cytotoxic activities.

A practical and green approach for the one-pot multicomponent synthesis of fused tetrazolo[1, 5-a]quinazoline derivatives has been described via the condensation of 5-aminotetrazole, dimedone, and various aldehydes using 1-butyl-3-methylimidazolium tetrachloroaluminate [bmim]Cl/AlCl3, as a catalyst and task-specific ionic liquid medium. The catalyst was showed remarkable advantages in comparison with previous methods. Short synthetic route, operational simplicity, high-to-excellent yields, eco-friendliness and mild reaction conditions are the advantages of this method.

The acidity constants of some synthesized protonated pyrazolo quinazoline compounds were determined potentiometrically at ionic strength of 0. 1 M in DMF: water (60: 40 v/v) system at different temperatures (298. 15 K to 318. 15 K). The pKa values have been found to increase with increasing electron-donating nature of substitutions. Some thermodynamics parameters such as enthalpy (Δ H° ), Gibb’ s free energy (Δ G° ) and entropy (Δ S° ) of reactions have also been evaluated at different temperatures for these systems. The thermodynamic parameters indicate that dissociation process is not spontaneous and exothermic.