Modified 7-Chloro-11H-Indeno[1,2-b]Quinoxaline Heterocyclic System for Biological Activities

Abstract

Recent advances in functionalized organic Spiro heterocyclic compounds composed of nitrogen bonded five-and six-membered rings have been made, establishing them as a synthetic target in organic-based biomedical applications. In this work, we report a synthesis of spirocyclic compounds under a one-pot reaction using 1,3-dipolar cycloaddition in a regio and diastereoselec-tive manner. The higher atomic economy with higher yield (95%) and regio and stereoselectivity were achieved by a multi-component reaction of L-proline (1), Indenoquinoxaline (2), and the dipo-larophile of malononitrile (3) solvents followed by reflux conditions. The reaction intermediate com-prised azomethineylides derived from reactive primary amines, and the spiro derivatives were synthesized up to a ≈ 95% yield. The structural and characteristic chemical components of the as-pre-pared Spiro compounds were characterized by1H-NMR, FTIR, and Mass spectroscopy. The func-tionalized spiro-pyrrolizidines were found to be effective for biological uses by considering their in vitro screening and antimicrobial impacts. Spiro constituents were found to be much more effective for Gram-positive bacteria due to the stronger lipophilic character of the molecules, and they re-sulted feasible membrane permeation in a biological system. Based on the planarity geometry of the Spiro pyrrolizidines, meta-substitution possesses steric hindrance and hence shows less effective-ness compared to para-substitution on the same nucleus, which shows a marginal steric effect. The biological studies showed that the derived spiro heterocyclic systems have an inhibitory effect of 50%.