Based on our experimental results, compounds that showed potent activity are those with a short carbon side chain; a methoxy group on the benzene ring; a heterocyclic (triazole) side chain and the presence of an alkylated N-atom at position 4.

In the title compound, C 13 H 9 BrClN 3 , the imidazopyridine fused-ring system is almost planar, with r.m.s. deviation of 0.006 (19) Å , and makes a dihedral angle of 29.32 (8) with the mean plane of the 4-chlorophenyl group. In the crystal, C-HÁ Á ÁN hydrogen bonds link the molecules into chains propagating in the [100] direction. Weak intermolecular -interactions between the five-and sixmembered rings of the 3H-imidazo [4,5-b]pyridine moieties of neighbouring molecules [centroid-centroid distance = 3.8648 (12) Å ] further consolidate the packing into layers parallel to the ab plane.

In the title compound, C19H13BrClN3, the chlorophenyl ring occupies an equatorial position with respect to the mean plane of the imidazopyridine unit, while the other phenyl ring is twisted by 4.1 (2)° with respect to the mean plane of the imidazopyridine unit. In the crystal, pairwise C—H...Br interactions link the molecules into dimers, forming anR22(16) ring motif. In addition, weak π–π stacking interactions stabilize the crystal packing.

In the title compound, C23H26BrClN6, the imidazo[4,5-b]pyridine ring system (r.m.s. deviation = 0.012 Å) is inclined at angles of 19.37 (12) and 89.27 (13)° to the phenyl and triazole rings, respectively, while the phenyl and triazole rings subtend a dihedral angle of 71.23 (15)°. In the crystal, the molecules are linked by C—H...NI and bifurcated C—H...(NT,NT) (I = imidazo[4,5-b]pyridine and T = triazole) hydrogen bonds into a double-column structure propagating along the b-axis direction.

The imidazo[4,5-b]pyridine unit is planar, while the phenyl and allyl substituents are rotated a little out of this plane. In the crystal, mol­ecules are linked via pairs of the weak inter­molecular C—H⋯N hydrogen bonds, forming inversion dimers with (20) ring motifs. The dimers are further connected by π–π stacking inter­actions between the imidazo[4,5-b]pyridine ring systems.