Crystal structure of (5-methyl-imidazo[1,2-a]pyridin-2-yl)methanol

Crystal structure and Hirshfeld surface analysis of two imidazo[1,2-a]pyridine derivatives: N-tert-butyl-2-(4-meth-oxy-phen-yl)-5-methyl-imidazo[1,2-a]pyridin-3-amine and N-tert-butyl-2-[4-(di-methyl-amino)-phen-yl]imidazo[1,2-a]pyridin-3-amine

In the title imidazo[1,2-a]pyridine derivatives, N-tert-butyl-2-(4-meth-oxy-phen-yl)-5-methyl-imidazo[1,2-a]pyridin-3-amine, C19H23N3O, (I), and N-tert-butyl-2-[4-(di-methyl-amino)-phen-yl]imidazo[1,2-a]pyridin-3-amine, C19H24N4, (II), the 4-meth-oxy-phenyl ring in (I) and the 4-(di-methyl-amino)-phenyl ring in (II) are inclined to the respective imidazole rings by 26.69 (9) and 31.35 (10)°. In the crystal of (I), mol-ecules are linked by N-H⋯N hydrogen bonds, forming chains propagating along the [001] direction. The chains are linked by C-H⋯π inter-actions, forming layers parallel to the (010) plane. In (II), the crystal packing also features N-H⋯N hydrogen bonds, which together with C-H⋯N hydrogen bonds link mol-ecules to form chains propagating along the c-axis direction. The chains are linked by C-H⋯π inter-actions to form layers parallel to the (100) plane. Inversion-related layers are linked by offset π-π inter-actions [inter-centroid distance = 3.577 (1) Å]. The inter-molecular inter-actions of both compounds were analyzed using Hirshfeld surface analysis and two-dimensional fingerprint plots.

(E)-2-Phenyl-N-(thiophen-2-ylmethylidene)imidazo[1,2-a]pyridin-3-amine

The asymmetric unit of the title compound, C18H13N3S, is build up from two independent molecules slightly inclined to each other. In each molecule, the imidazo[1,2-a]pyridine ring system is almost planar, with the largest deviation from the mean plane being 0.022 (1) Å in the first molecule and 0.018 (1) Å in the second molecule. The fused-ring system belonging to the first molecule makes dihedral angles of 24.06 (7) and 40.52 (8)° with the thiophenyl and phenyl rings, respectively. The corresponding values observed in the second molecule are nearly the same, namely 25.20 (7) and 38.99 (7)°, respectively. The dihedral angle between the thiophenyl and phenyl rings is 63.47 (9)° in the first molecule and 47.49 (9)° in the second. The cohesion of the crystal structure is ensured by two C—H...N hydrogen bonds between molecules and by three C—H...π interactions, forming a three-dimensional network.

Crystal structure of 2-(4-meth-oxy-phen-yl)-6-nitro-imidazo[1,2-a]pyridine-3-carbaldehyde

In the title compound, C15H11N3O4, the imidazo[1,2-a] pyridine ring system is almost planar [r.m.s. deviation = 0.028 (2) Å]. Its mean plane makes dihedral angles of 33.92 (7) and 34.56 (6)° with the meth-oxy-phenyl ring and the nitro group, respectively. The cohesion of the crystal structure is ensured by C-H⋯N and C-H⋯O hydrogen bonds, forming layers almost parallel to the ac plane.

Crystal structure of (E)-4-[N-(7-methyl-2-phenyl-imidazo[1,2-a]pyridin-3-yl)carboximido-yl]phenol

The mol-ecule of the title compound, C21H17N3O, is built up from fused five- and six-membered rings connected to a methyl group, a phenyl ring and an (imino-meth-yl)phenol group. The fused ring system is almost planar (r.m.s. deviation = 0.031 Å) and forms dihedral angles of 64.97 (7) and 18.52 (6)° with the phenyl ring and the (imino-meth-yl)phenol group, respectively. In the crystal, centrosymmetric mol-ecules are linked by pairs of C-H⋯π inter-actions into dimeric units, which are further connected by O-H⋯N hydrogen bonds to form layers parallel to (101).