Diethyl 2-(2,3-diphenylquinoxalin-6-ylaminomethylene)malonate

Abstract

The substituted aminoethylenic group in the title compound, C28H25N304, is approximately coplanar with the heterocyclic plane [dihedral angle 16 (2) °] and the a-C atom C(23), is disordered between two well defined sites. This disorder originates from a flipping of the aminoethylenic moiety around the © 1994 International Union of Crystallography Printed in Great Britain -all fights reservedActa Crystallographica Section C ISSN 0108-2701 ©1994 LOKAJ, KETI'MANN, VRA, BEL, ILAVSK~" AND MILATA 1785 C(6)---N(5) bond. The phenyl rings at C(2) and C(3) are twisted out of the plane of the quinoxaline ring system by 46.7 (8) and 38.0 (9) ° , respectively. CommentThe overall conformation of the title molecule (I) and the numbering scheme are shown in Fig. 1. The dihedral angles that the phenyl groups make with the planar quinoxaline moiety in the title compound [46.7 (8) Fig. 1. Perspective drawing of the title compound and atomnumbering scheme. Displacement ellipsoids are drawn at the 40% probability level. Only one of the two disordered sites for C(23) is shown.As a consequence of the disorder of the methylenic atom C(23), the N(5)--C(231) and N(5)---C(232) bond lengths are very short, while the C(231)--C(24) and C(232)---C(24) distances are unusually long (Table 2). Other bond distances and angles in those parts of the molecule not affected by the disorder are quite normal.The substituted aminoethylenic moiety is approximately planar with the relevant torsion angles around the N(5)--C(23) bond being C(6)--N(5)--C(231)---C(24) = -179.2 (6) and C(6)--N(5)--C(232)--C(24) = -179.3 (9) °. Although a fast rotation around the C(6)---NH bond in several related compounds has been reported to occur in solution (Goljer, Milata & Ilavsk~,, 1989), the occurence of the two conformations of the aminoethylenic group has not yet been observed in the solid state. Experimental Crystal data118.5 (6) C (8) There is a twofold disorder at the C(23) atom and occupancy factors were fixed at 0.50 for both sites, C(231) and C(232), based on relative heights in a difference Fourier map. Positions of the H atoms, except those attached to the disordered C atom and its neighbouring N atom, were calculated and included in the Fc calculation with Biso set at 0.5/~2 higher than the Beq value of the parent C atom. The structure was solved using MULTAN80 (Main, Fiske, Hull, Lessinger, Germain, Declercq & Woolfson, 1980). All remaining calculations were performed with a local version of the NRC program system (Ahmed & Singh, 1973 AbstractThe title compound [N,N'-bis(benzoylphenyl)methanediamine, C27H22N202] was prepared by condensation of 4-aminobenzophenone (ABP) and formaldehyde at room temperature. In the molecule, two ABP moieties are linked by a methylene group. The bond lengths and angles within the two ABP groups are very similar; however, the dihedral angles between the sets of ring planes are quite different [83.1 (5) and 57.5 (3)°]. CommentRecently, crystals of 4-aminobenzophenone (ABP) were discovered to be a new and highly e...

Diethyl 2-{[(5-oxo-5H-thiochromeno[2,3-b]pyridin-7-yl)amino]methylidene}propanedioate

“…For related structures, see: Khan et al (2008a,b); Lokaj et al (1994); Lynch & McClenaghan (2003); For graph-set notation, see: Etter et al (1990); Bernstein et al (1995). (11) 135Symmetry codes:…”

“…1) is in continuation of our work to synthesize the derivatives of 5H-thiochromeno[2,3-b]pyridin-5-one. The crystal structures of (IV) i.e., diethyl 2-(2,3-diphenylquinoxalin-6-ylaminomethylene)malonate (Lokaj et al, 1994) and (V) i.e., diethyl (4-tert-butyl-1,3-thiazol-2-ylaminomethylene)malonate (Lynch & McClenaghan, 2003) have been published. Both contain the diethyl (aminomethylidene)propanedioate moiety which is also present in (I).…”