CES as an Efficient Natural Catalyst for Synthesis of Schiff Bases under Solvent-Free Conditions: An Innovative Green Approach

Abstract

A mild and efficient method has been reported for the preparation of Schiff base ligands through the condensation reaction of various aromatic aldehydes with substituted aromatic amines in the presence of CES (calcined eggshell) as a heterogeneous catalyst under solvent-free conditions. The advantages of this ecofriendly, economic method are simplicity of the reaction procedure, moderate to good product yields, and very short reaction times.

Biogenic derived egg shell and its derivatives as solid base heterogeneous catalysts for organic transformations: a comprehensive review

“…ES powder was used as a catalyst for the synthesis of Schiff bases under solvent free conditions. 18 These will bond coordinately with metals to form metal complexes and are used as models for biological systems. 19 Numerous research studies have explored the synthesis of Schiff bases, 20,21 but they faced constraints such as long reaction time, low yield, use of toxic solvents and tedious workup procedures.…”

Toward Renewable Amines: Recent Advances in the Catalytic Amination of Biomass-Derived Oxygenates

“…191 The reaction involves the formation of an alkoxide complex in the first step by adsorption of an alcohol 252,253 However, the reaction between carbonyl species and amines is considered noncatalytic during reaction which needs to be further confirmed as similar reactions are proposed to occur over nonmetallic catalysts. 254,255 Abbenhuis et al reported the effect of the base in the Ru-catalyzed amination reaction cycle Figure 14B. 188 It is proposed that the base enhances the formation of Ru-alkoxy species by an efficient abstraction of hydrogen leading to a protonated base.…”

Synthesis, Spectral Characterization, and Antimicrobial Activity of Two Novel Schiff Bases Derived from Thiosemicarbazide and Mononuclear 3d Transition Metal Complexes

“…The importance of carbazides, carbazones, thiosemicarbazide, and their transition metal complexes has grown in a short period of time because of the discovery of their effects on flu, protozoa, variola (smallpox), certain types of tumors, and fungi [13][14] and their corresponding derivatives thiosemicarbazide are related to several essential antimicrobial activities 15 . Fungicidal, anthelmintic, anti-bacterial, activity 16 . Schiff bases derived from simple thiosemicarbazide and its derivatives are found to be very effective in the field of pharmacology and other imp medicinal fields 17 .…”