Crown ether functionalized magnetic hydroxyapatite as eco‐friendly microvessel inorganic‐organic hybrid nanocatalyst in nucleophilic substitution reactions: an approach to benzyl thiocyanate, cyanide, azide and acetate derivatives

Abstract

In this paper, high catalytic activity of 4′,4″‐diformyl dibenzo‐18‐crown‐6 anchored onto the functionalized magnetite hydroxyapatite (γ‐Fe2O3@HAp–Crown) as a new, versatile and magnetically recoverable catalyst, was prepared. It evaluated as phase‐transfer catalyst and molecular host system for nucleophilic substitution reactions of benzyl halides with thiocyanate, cyanide, azide and acetate anions in water. No evidence for the formation of by‐products was observed and the products obtained in pure form without further purification. The nanocomposite was easily removed from solution via application of a magnetic field, allowing straightforward recovery and reuse. The synthesized nanocomposite was characterized by several techniques such as FT‐IR, TGA‐DTG, EDX, XRD, BET, FE‐SEM, TEM and VSM.

Selenonium Salt as a Catalyst for Nucleophilic Substitution Reactions in Water: Synthesis of Thiocyanites and Selenocyanates

“…Not surprisingly, the search for methods to prepare these valuable compounds has attracted much attention. They can be prepared, for instance, with the aid of phase transfer catalysts [ 27 , 28 , 29 , 30 , 31 ], in free radical reactions [ 32 , 33 , 34 , 35 ], by electrophilic addition to suitable organic substrates [ 36 , 37 ], or in reactions employing ionic liquids as a solvent and the nucleophilic source of chalcogen cyanide [ 38 ]. In this contribution, we share our findings on the use of selenonium salts to activate substrates such as benzyl bromides through chalcogen bond interactions, facilitating the displacement reaction with KChCN (Ch = S or Se) using a 20:1 mixture of water and dimethyl carbonate as a solvent.…”