Zinc (II) Chloride as Phase Transfer Catalyst and as Catalyst of Cycloaddition Azide Ion to Heterocumulenes and Terminal Alkynes in Organic Solvents

Abstract

The system of NaN 3 -ZnCl 2 in organic solvents is effective for azide ion cycloaddition to heterocumulenes and terminal alkynes. The reaction proceeds readily in the case of heterocumulenes, so these transformations fall into the category of click reactions. The study on the reaction mechanism showed that role of zinc salt consists in transferring azide ion to the organic phase and decreasing the energy barrier of nucleophilic addition of azide ion to the unsaturated substrate.[a] S. Scheme 1. Cycloaddition of azide to nitriles and heterocumulenes Scheme 2. Preparation of mixed zinc salt ZnClN 3

An eco‐friendly synthesis of 5‐aminotetrazoles using trichloroisocyanuric acid as desulfurization agent of thioureas

“…Although there are a considerable number of procedures for the preparation of 5-aminotetrazoles from ketones [13], cyanamides [14], carbodiimides [15], primary amines/cyanogen azide [16], or selenoureas [17], methodologies involving the oxidative desulfurization of thioureas to carbodiimides followed by azidation proved to be more convenient and versatile. Traditional reagents used for the desulfurization of thioureas include various metal salts [18], molecular iodine [19], and hypervalent iodine compounds [20] (Scheme 1).…”

Synthesis of 1,4-Biphenyl-triazole Derivatives as Possible 17β-HSD1 Inhibitors: An in Silico Study

“…The click conjugation includes direct utilization of copper­(I) salts, either added directly or generated by reduction of copper­(II) or oxidation of Cu(0) and copper complexes . There are also examples of CuAAC reactions by the heterogeneous catalyst using materials such as alumina, silica, polymers, zeolites, or activated carbon as supports. − Other catalytic systems used are Ru-, Zn-, Ag-, Ni-, Pt-, and Pd-catalyzed click. − The efficiency of the azide/alkyne click reaction was improved by the use of microwave irradiation and ultrasonication. ,, …”