Spirocyclic compounds isolated from plant and animal origins have important applications in medicinal chemistry. Spiro compounds having cyclic structures fused at a central carbon are of recent interest because of their interesting conformational features and their structural implications for biological systems. Spiro heterocycles like spiropyrrolidines and oxindole moieties have been found to play fundamental roles in biological processes and have exhibited diversified biological activity and pharmacological and therapeutical properties. In view of these facts we decided to present a representative synthetic scheme and various biological activities of the heterocycles like spiropyrrolidines and oxindole moieties derivatives, especially in relation to microbial infections like cancer and tubercular, viral, HIV, bacterial, and fungal infections.

To explore the pharmacological and structure–activity relationship of a series of N-substituted-(4-oxo-2-substituted-phenylquinazolin-3-(4H)-yl), substituted benzene sulfonamide derivatives (1–25) were synthesized from substituted anthranilic acids derived amino quinazolines and substituted benzene sulphonamides. All the synthesized compounds were evaluated for their diuretic (by Lipschitz et al. method), antihypertensive activity by non-invasive blood pressure (NIBP) using the tail-cuff method and anti-diabetic potential in rats. Six compounds showing significantly excellent activity were compared with metolazone, prazosin and diazoxide as standards. Compound N-[7-chloro-2-(4-methoxyphenyl)-4-oxoquinazolin-3(4H)-yl]-4 nitrobenzenesulfonamide (20) exhibited most potent of the series.

Cytotoxicity and genotoxicity of anticancer drugs to the normal cells are major problems in cancer therapy and endanger the risk of inducing secondary malignancy. Current regimen with anticancer drugs produces various toxicities. Therefore, there is urgent need for the development of newer and safer drugs. Quinazoline derivatives occupy a pivotal position in modern medicinal chemistry and have found applications as medicines. Various researches have been performed on quinazoline and their derivatives for anticancer activity and pharmacological importance of this scaffold has been well established. Quinazoline reported to possess a number of biological activities. It has multiple pharmacophores, which bring together knowledge of a target with understanding of the molecule types that might interact with the target family. The current review focuses on biological actions done for various targets along with the brief description of the targets which may facilitate the development of more potent and effective anticancer agents. GRAPHICAL ABSTRACT

A series of 7-substituted-3-(4-(3-(4-substitutedphenyl)-4,5-dihydroisoxazol-5-yl)phenyl)-2-substituted quinazolin-4(3H)-one(1–30)have been synthesized by the cyclization of (E)-3-(4-(3-substitutedphenyl)acrylolyl)phenyl)-2-(substitutedphenyl)-7-substituted quinazolin-4-(3H)-one with hydroxylamine hydrochloride. The synthesized compounds were examined for theirin vivoantihypertensive activity using albino rats. All the titled compounds exhibited good to moderate antihypertensive activity. Compounds 7-Chloro-3-(4-(3-(4-chlorophenyl)-4,5- dihydroisoxazol-5-yl)phenyl)-2-p-tolylquinazolin-4(3H)-one(23)and 7-Chloro-3-(4-(3-(4-chlorophenyl)-4,5-dihydroisoxazol-5-yl)phenyl)-2-(4-methoxyphenyl)quinazolin-4(3H)-one(24)exhibited potent antihypertensive activity through their anticipatedα₁-adrenergic receptor blocking property similar to its clinically used analogue, prazosin, without affecting heart rate with prolonged duration of action when tested in adrenaline induced hypertension in anaesthetized rats.