A series of three (E)-2-alkylidene-1,4-di-p-tosyl-1,2,3,4-tetrahydroquinoxaline compounds

Abstract

The three title quinoxaline derivatives, (E)-2-(4-methylbenzylidene)-1,4-di-p-tosyl-1,2,3,4-tetrahydroquinoxaline, C30H28N2O4S2, (II), (E)-2-(4-methoxybenzylidene)-1,4-di-p-tosyl-1,2,3,4-tetrahydroquinoxaline, C30H28N2O5S2, (III), and (E)-2-(3-chlorobenzylidene)-1,4-di-p-tosyl-1,2,3,4-tetrahydroquinoxaline, C29H25ClN2O4S2, (IV), were synthesized by palladium-catalyzed hetero-annulation. The E configuration of the exocyclic double bond in the three compounds has been established by the present X-ray study. The saturated part of the quinoxaline moiety in all three compounds assumes a distorted chair conformation. The numerical descriptors indicate a high degree of isostructurality between compounds (II) and (III), but no isostructurality with compound (IV).

Two (E)-2-arylidene-1,4-di-p-tosyl-1,2,3,4-tetrahydroquinoxaline compounds: supramolecular frameworks built with C—H...O and C—H...π(arene) hydrogen bonds and π–π stacking interactions

“…The molecular geometries of (II) and (III) ( Tables 1 and 3) agree well with the corresponding values reported for similar N-substituted quinoxaline compounds (Banerjee et al, 2001). The sums of the valence angles at the two N atoms (N1 and N2) of the pyrazine ring are 349.1 (1) and 348.5 (1) , respectively, for (II), and 348.2 (1) and 347.8 (1) , respectively, for (III), deviating signi®cantly from 360 , showing that these atoms display pyramidal distortion.…”

“…The similarity of the lattice parameters and space groups between (II) and other N-substituted quinoxaline compounds reported earlier by Banerjee et al (2001) A view of (III), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 40% probability level and H atoms are shown as small spheres of arbritary radii.…”

“…The DNA photocleaving property of quinoxaline-based compounds with substitutions at the Cpositions of the pyrazine ring has been attributed to the conjugated C N bonds in these systems (Toshima et al, 2002). Although the syntheses and crystal structure analyses of different C-substituted quinoxalines have been reported (Dobrzan  ska & Lloyd, 2005; Zhao & Du, 2003;Sessler et al, 2002;Chowdhury et al, 2001), the corresponding reports of N-substituted quinoxalines have been rather sparse (Banerjee et al, 2001). As part of an ongoing programme on the synthesis and structural characterization of novel N-substituted quinoxalines, we synthesized two 2-alkylidene-1,4-di-ptosyl-1,2,3,4-tetrahydroquinoxalines via palladium-catalyzed hetero-annulation of N-substituted phenylamines.…”

Synthesis, spectroscopic and X-ray structure analyses of two N-[(3′-aryl) prop-2′-ynyl]-N,N′-1,2-phenylene di-p-tosylamides

“…The acyclic phenyl diamides, with several NH/CH groups, O/N atoms and phenyl rings, offer the possibility for N--HÁ Á ÁO, C--HÁ Á ÁO, C--HÁ Á Áp and p--p interactions between molecules in the solid state [6]. As a continuation of our studies of novel heterocyclic systems having biological importance [7,8], X-ray structure analyses of the title compounds, N-[(3 0 -2-Thienyl) prop-2 0 -ynyl]-N,N 0 -1, 2-phenylenedi-p-tosylamide(I) and N-[(3 0 -3-Chlorophenyl) prop-2 0 -ynyl]-N-N 0 -1,2-phenylenedi-p-tosylamide(II), two potential intermediates leading to N-substituted quinoxaline systems, have been undertaken. The synthesis, spectroscopic charecterization, molecular and supramolecular structures of the title tosylamides are reported here.…”

2-p-Toluoylquinoxaline

“…Many quinoxaline derivatives display unusual solid-tumor selectivity against multidrug-resistant cancer cells (Gao et al, 1999). The synthetic utility and pharmacological importance of these compounds have prompted us to synthesize and characterize novel quinoxaline derivatives (Banerjee et al, 2001). During the synthesis of a di-p-tosyl-1,2,3,4-tetrahydroquinoxaline, (II), via a palladium±copper catalyzed reaction, an unexpected product, namely 2-p-toluoylquinoxaline, (III), was obtained in good yield.…”