Regioselectivity and regiospecificity of benzoxazinone (2-isopropyl-4<i>H</i>-3,1-benzoxazinone) derivatives toward nitrogen nucleophiles and evaluation of antimicrobial activity

Abstract

<p>A novel group of 6-iodoquinazolin-4(<i>3H</i>)-one derivatives was prepared. The reaction of the benzoxazinone <b>3</b> with various nitrogen nucleophiles such as formamide and hydrazine hydrate and also the reaction of the isopropylquinazolinone <b>4</b> with hydrazonyl chloride have been shown to proceed with a high degree of regioselectivity at C(2). Spiro heterocycles have been found to play fundamental roles in biological processes and have exhibited diversified biological activity and pharmacological and therapeutical properties; thus reaction of acetohydrazides <b>10a–c</b> afforded the spiro compounds <b>11a–c</b>. The acetohydrazide derivative <b>7</b> reacted with carbon electrophiles such as acetylacetone, ethyl acetoacetate, acid chlorides, and benzaldehyde to give some interesting heterocyclic compounds <b>12–16</b>, respectively. The structures of all the synthesized compounds were inferred by infrared, ¹H NMR, and mass spectra as well as elemental analyses. The antimicrobial activities of some of the synthesized products were preliminarily evaluated.</p