Pd-S-methylisothiourea complex supported on boehmite nanoparticles: as efficient synthesis of 5-substituted tetrazoles

In the last decades, supporting of homogeneous catalysts on various heterogeneous solids has been studied as recyclable catalysts. However, many supports such as TiO2 NPs, MCM- 41, SBA-15, iron oxide, carbon nanotubes, heteropolyacids, graphene oxide, ionic liquids, molecular sieve or some polymers have been used as heterogeneous catalysts or as support for homogeneous catalysts, which most of them is expensive, requires inert atmosphere or high temperature for calcination and a lot of time and tedious condition to prepare [1]. While synthesis of boehmite was not moisture or air sensitive, also boehmite was synthesized in H2O at room temperature using available materials. Nanoboehmite have several attractive features such as stability, non-toxicity, high dispersion of the active phases, high specific surface area, ease of surface modification, readily and easily available, and favorable biocompatibility. Although boehmite nanoparticles has been rarely employed as heterogeneous support [2]. Therefore herein a moisture- and air stable Pd-SMTU@boehmite has been reported as new organometallic catalyst for the synthesis of tetrazole derivatives. Because tetrazoles are important heterocyclic compounds, containing several applications in organic synthesis, material science, coordination chemistry, and medicinal chemistry. For example, Valsartan and Losartan are two typical examples of the extensive application of these compounds in drugs. Also tetrazoles and their derivatives have been reported as antiviral, antibacterial, anti-inflammatory herbicidal, potential anti HIV drug candidate, antiproliferative, analgesic, and antitumor agents [3, 4]. Thus the synthesis of these heterocycles has become an area of great interest.