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...[pi](arene) hydrogen bonds and [pi]-[pi] stacking inter­actions

The pyrazine ring in two N-substituted quinoxaline derivatives, namely (E)-2-(2-methoxy­benzyl­idene)-1,4-di-p-tosyl-1,2,3,4-tetra­hydro­quin­oxaline, C₃₀H₂₈N₂S₂O₅, (II), and (E)-methyl 2-[(1,4-di-p-tosyl-1,2,3,4-tetra­hydro­quinoxalin-2-yli­dene)methyl]benzoate, C₃₁H₂₈N₂S₂O₆, (III), assumes a half-chair conformation and is shielded by the terminal tosyl groups. In the mol­ecular packing of the compounds, inter­molecular C-H...O hydrogen bonds between centrosymmetrically related mol­ecules generate dimeric rings, viz. R₂²(22) in (II) and R₂²(26) in (III), which are further connected through C-H...[pi](arene) hydrogen bonds and [pi]-[pi] stacking inter­actions into novel supra­molecular frameworks.