Quinoxalines Derived from D-Xylose and o-Phenylenediamine under Acidic Refluxed Conditions

Abstract

Quinoxalines derived from D-xylose and o-phenylenediamine (OPD) in an acidic medium under reflux were studied, using GLC, GC-MS and NMR measurements.
Three quinoxaline derivatives (XA-I, XA-II and G-2) were separated from the reaction mixture of D-xylose with OPD (0.2 mol, each) in a 46% total yield. Their approximate molar ratio was 3:3:2. Two newly isolated XA-I and XA-II derivatives were identified as 2-methyl-3-(2'-hydroxyethyl) quinoxaline and 2-(1', 2', 3'-trihydroxypropyl) quinoxaline, respectively. The other was G-2 [2-(2', 3'-dihydroxypropyl) quinoxaline], which has previously been obtained from D-glucose or D-xylose in an alkaline solution. XA-I may be regarded as a partially reduced form of G-2 at the side chain of the quinoxaline, with XA-II as an oxidized form. A possible mechanism for quinoxaline formation is discussed.