ORIENTAL JOURNAL OF CHEMISTRY www.orientjchem.org An International Open Free Access, Peer Reviewed Research Journal ISSN: 0970-020 X CODEN: OJCHEG 2017, Vol. 33, No. (2): Pg. 562-574 Expeditious Synthesis and Spectroscopic Characterization of 2-Methyl-3-substituted-quinazolin-4(3H)-one Derivatives OLAYINKA O. AJANI 1 *, OLUWATOSIN Y. AUDU 1 , MARKUS W. GERMANN 2 and BABATUNDE L. BELLO 2 1 Department of Chemistry, Covenant University, CST, Canaanland, Km 10 Idiroko Road, P.M.B. 1023, Ota, Ogun State, Nigeria. 2 Department of Chemistry, Georgia State University, Atlanta GA, 30302, USA. *Corresponding author E-mail: ola.ajani@covenantuniversity.edu.ng http://dx.doi.org/10.13005/ojc/330203 (Received: June 18, 2016; Accepted: March 29, 2017) ABSTRACT Quinazoline and quinazolinone derivatives are well-known bioactive heterocycles owing to their therapeutic diversity and extensive medicinal application in drug design and pharmaceutics. A series of 2-methyl-3-substituted quinazolin-4(3H)-one derivatives 8a-q was herein synthesized from synthetic conversion of anthranilic acid to 2-methyl-4H-3,1-benzoxazi-4-one, 7 which was subsequently transformed to the targeted 2,3-disubstituted quinazolin-4(3H)-one derivatives 8a-q by reacting with some notable amino-containing moieties via an ameliorable pathway. The catalyst- free synthesis was successful achieved by careful reaction optimization study using solvent choice and reaction temperature variability as key parameters. The chemical structures of the synthesized compounds were confirmed by IR, UV, 1 H-NMR, 13 C-NMR and DEPT-135 as well as analytical data. Keywords: Solvent-dependent synthesis, spectral study, quinazolin-4(3H)-one, DEPT-135 analysis. INTRODUCTION Heterocyclic compounds form the basis for pharmaceutical industry especially in the synthesis of drugs 1 . Also, most marketed drugs constitute of common structural units of heterocyclic compounds which could also be useful in the synthesis of biologically active agrochemicals 2,3 . For instance, in the pharmaceutical industry, among the top two hundred branded drugs, we have more than 75% of them which have heterocyclic fragments in their structures 4 . One of these organic compounds of interest among the heterocycles is quinazoline otherwise known as 1,3-diazanaphthalene, benzo- 1,3-diazine, benzopyrimidine which was first synthesized by Gabriel in 1903 5 . Quinazoline can have different types of substituents attached to it, forming different derivatives of the parent