1Department of Chemistry, Faculty of Science, University of Lorestan, Khorramabad, I.R. IRAN
2Department of Biology, Faculty of Science, Tarbiat Modares University, Tehran, I.R. IRAN
2,5,10,13-Tetraazatricyclo [12,2,2,26,9] icosa-1(16),6,8,14,17,19-hexene-3,4,11,12-tetraone tetraoxime (1a) and 2,5,11,14-tetraazatricyclo [13,3,1,16,10] icosa-1(19),6,8,10(20),15,17-hexaene-3,4,12,13-tetraonetetraoxime (1b) were obtained from condensation of 1,4- and 1,3-phenylendiamine with dichloroglyoxime, respectively. The reaction of 1,2-phenylendiamine with dichloroglyoxime resulted in the production of (2Z,3Z)-1,4-dihydroquinoxaline-2,3-dione dioxime (2). The x-ray structure determination of compound 2 shows the piprazine ring is rather planar relative to the fused aromatic ring. The results show that a resonance occurs between the aromatic ring and the C=N bond, through N4 and N3 atoms of the molecule. The results from x-ray data, indicated that the molecules 2 could exist as a dimmer by intermolecular hydrogen bonding between NH and OH groups.