FeCl3–SiO2 as a reusable heterogeneous catalyst for the synthesis of 5-substituted 1H-tetrazoles via [2+3] cycloaddition of nitriles and sodium azide

FeCl3–SiO2 as heterogeneous catalysts for the preparation of dihydropyrano[3,2-b]chromenediones

FeCl3–SiO2 is environment-friendly heterogeneous catalyst for the condensation of kojic acid and aldehydes with dimedone to afford dihydropyrano[3,2-b]chromenediones. The solid acid catalyst is stable and can be easily recovered and reused without appreciable change in its efficiency.

4-[4-(1H-Tetra-zol-5-yl)phen-oxy]benzaldehyde

The asymmetric unit of the title compound, C(14)H(10)N(4)O(2), contains two independent mol-ecules with similar structures. In one mol-ecule, the tetra-zole ring is oriented at dihedral angles of 17.71 (16) and 57.13 (17)°, respectively, to the central benzene ring and the terminal benzene ring; in the other mol-ecule, the corresponding dihedral angles are 16.46 (18) and 75.87 (18)°. Inter-molecular N-H⋯N hydrogen bonds and weak C-H⋯O and C-H⋯N hydrogen bonds occur in the crystal structure.

Ferric Hydrogensulfate [Fe(HSO4)3] As a Reusable Heterogeneous Catalyst for the Synthesis of 5-Substituted-1H-Tetrazoles and Amides

Ferric hydrogensulfate catalyzed the synthesis of 5-substituted 1H-tetrazoles via [2 + 3] cycloaddition of nitriles and sodium azide. This method has the advantages of high yields, simple methodology, and easy workup. The catalyst can be recovered by simple filtration and reused delivering good yields. Also, ferric hydrogensulfate catalyzed the hydrolysis of nitriles to primary amides under aqueous conditions. Various aliphatic and aromatic nitriles converted to the corresponding amides in good yields without any contamination with carboxylic acids.