Synthesis of Novel 2,3-Disubstituted Quinazolin-4-(3H)-ones and Their Antibacterial Activity on the Ultra-structure of Some Pathogenic Microorganisms

Abstract

The fused heterocyclic quinazolin-4-one and related derivatives are of considerable interest due to their wide range of biological properties, for example, anti-tumor[1], antimicrobial [2], antifungal [3] and antibacterial [4]. Moreover, the quinazolin-4-one ring is a frequently encountered unit in natural products, such as L-Vasicinone[5] and chrysogine [6] and in drugs, such as methaqualone [7], isofebrifugine [8] and febrifugine [9]. Aforementioned findings prompted the authors to synthesize a variety of new 2,3-disubstituted quinazolin-4-one derivatives, using the key starting 6-bromo-2-undecylbenzo [3,1] oxazin-4-one [10]. Furthermore, some of the prepared quinazolin-4-one derivatives were used as precursors for synthesis of 1,3-thiazolidin-4-ones and its derivatives which is an important ring for its wide biological applications [11][12][13]. Thus, by merging of these two biologically active hetero-rings together, it was hoped to obtain some new compounds of anticipated pharmaceutical interest. University, Mrorst., 62517, East Beni-Suef, Beni-Suef, Egypt, е-mail: fathykhaled905_7@yahoo.com A SERIES of highly functionalized quinazolin-4-ones, with different substituents at position 3, have been concisely synthesized in good yields, via the reactions of 3-amino-6-bromo-2-undecyl-quinazoline-4(3H)-one with one carbon donor phenyl isothiocyante, followed by α-chlorinated compounds and 1,2-dichloroethanone. Moreover, reactions of 6-bromo-2-undecyl-4H-benzo-[3,1]oxazin-4-one with different hydrazides were also examined, giving new 3-substituted quinazolin-4-one derivatives. Some of the new quinazolin-4-ones were screened against gram negative and positive bacteria and showed good to moderate antibacterial activity. Structures of all new synthesized compounds in this investigation were substantiated using spectroscopic IR, 1 H-NMR and MS studies. Synthesis of Novel