γ-Alumina Nanoparticle Catalyzed Efficient Synthesis of Highly Substituted Imidazoles.

γ-Alumina nano particle catalyzed multi component reaction of benzil, arylaldehyde and aryl amines afforded the highly substituted 1,2,4,5-tetraaryl imidazoles with good to excellent yield in less reaction time under the sonication as well as the conventional methods. Convenient operational simplicity, mild conditions and the reusability of catalyst were the other advantages of this developed protocol.

N-(4-Fluoro-phen-yl)-2,6-dimethyl-1,3-dioxan-4-amine.

In the title compound, C12H16FNO2, the dioxane ring adopts a chair conformation with the methyl substituents and the C-N bond in equatorial orientations. Its mean plane subtends a dihedral angle of 40.17 (6)° with the benzene ring.

N-(4-Meth-oxy-phen-yl)-2,6-dimethyl-1,3-dioxan-4-amine.

In the title compound, C13H19NO3, the dioxane ring adopts a chair conformation. Its mean plane is inclined to the 4-meth-oxy-phenyl ring by 70.34 (9)°.

N-(4-Bromo-phen-yl)-2,6-dimethyl-1,3-dioxan-4-amine.

In the title compound, C12H16BrNO2, the dioxane ring adopts a chair conformation and its mean plane makes a dihedral angle of 60.63 (12)° with the 4-bromo-phenyl ring. In the crystal, mol-ecules are linked by pairs of N-H⋯O hydrogen bonds, forming inversion dimers with an R 2 (2)(8) ring motif.

2,6-Dimethyl-N-(2-methyl-phen-yl)-1,3-dioxan-4-amine.

In the title compound, C13H19NO2, the dioxane ring adopts a chair conformation and its mean plane makes a dihedral angle of 45.36 (8)° with the phenyl ring. In the crystal, mol-ecules are linked by pairs of N-H⋯O hydrogen bonds, forming inversion dimers with R (2) 2(12) ring motifs.

N-(2-Fluoro-phen-yl)-2,6-dimethyl-1,3-dioxan-4-amine.

In the title compound, C12H16FNO3, the dioxane ring adopts a chair conformation with the methyl groups and amine N atom in equatorial positions. The best plane through the dioxane ring makes a dihedral angle of 43.16 (8)° with the phenyl ring.