Structure Reports Online

Volume 67, Part 10 (October 2011)

organic compounds

bt5632 scheme

Acta Cryst. (2011). E67, o2551 [ doi:10.1107/S1600536811035288 ]

6-Chloro-3-(3-methylphenyl)-1,2,4-triazolo[4,3-b]pyridazine

J. Preis, D. Schollmeyer and H. Detert

Abstract: The title compound, C₁₂H₉ClN₄, was prepared from dichloropyridazine and tolyltetrazole in a nucleophilic biaryl coupling followed by thermal ring transformation. The molecule is essentially planar (r.m.s. deviation for all non-H atoms = 0.036 Å) and an intramolecular C-HN hydrogen bond occurs. In the crystal, the molecules form dimers connected via [pi] - [pi] interactions [centroid-centroid distance = 3.699 (2) Å], which are further connected to neighbouring molecules via C-H-N bonds. The bond lengths in the pyridazine ring system indicate a strong localization of the double bonds and there is a weak C-Cl bond [1.732 (3) Å].