Three 4,7-diaryl-2-ethylsulfanylpyrazolo[1,5-a][1,3,5]triazines.

The molecular dimensions of 2-ethylsulfanyl-7-(4-methylphenyl)-4-phenylpyrazolo[1,5-a][1,3,5]triazine, C20H18N4S, (I), 7-(4-chlorophenyl)-2-ethylsulfanyl-4-phenylpyrazolo[1,5-a][1,3,5]triazine, C19H15ClN4S, (II), and 4,7-bis(4-chlorophenyl)-2-(ethylsulfanyl)pyrazolo[1,5-a][1,3,5]triazine, C19H14Cl2N4S, (III), show evidence for some aromatic delocalization in the pyrazole rings. The conformations adopted by the ethylsulfanyl substituents are different in all three compounds. There are no hydrogen bonds in any of the crystal structures, but pairs of molecules in (II) and (III) are linked into centrosymmetric dimers by pi-stacking interactions.