Claisen‐Schmidt Condensation using Green Catalytic Processes: A Critical Review

Abstract

Claisen‐Schmidt condensation have historical significance for over140 years and the scope was expanded due to the realization that chalcones so synthesized possess biological activity. The principles of green chemistry with emphasis on use of different solid catalysts with proper distribution of active centers such as acid, base, acid‐base, organo‐ were used along with solvent‐less systems. Among solid bases layered double hydroxides (LDH)/hydrotalcites are the most common. The limitations of solid bases are overcome by solid acids and superacids. A number of metal oxide supports are used. MOFs are increasingly being used. Complex organo‐catalysts are employed for getting excellent regio‐selectivity. In certain metal oxides, both acidic and basic sites co‐exist on the pore surface of catalyst which offer superior results. Synergism of solid catalysis using microwaves and ultrasound to intensify rates and selectivity is in vogue.Controlled pore structure and distribution of active catalytic centers, whether mono‐, bi‐ or tri‐functional catalysts, will give better green and smart processes. The review gives a critical analysis of the area and presents future directions for research.

Microwave-Assisted Claisen-Schmidt Condensation Reaction of Ethyl p-methoxycinnamate to Synthesize p-Methoxystyryl Ketone Derivatives and Evaluate Anti-inflammatory Activity of Synthetic Products

“…Claisen-Schmidt condensation is a reaction that occurs when an aromatic carbonyl compound that does not have α-hydrogen reacts with aldehydes or ketones that have α-hydrogen. α,β-Unsaturated ketones such as chalcones, flavanones, and styryl ketones are typically synthesized using this reaction [16,23]. Recently, effective Claisen-Schmidt condensation reactions have been conducted through a microwave-assisted reaction between ketones and aromatic substituted aldehyde to synthesize α,β-unsaturated ketone compounds [16,24].…”

Recent Advances in bis-Chalcone-Based Photoinitiators of Polymerization: From Mechanistic Investigations to Applications

“…Bis-chalcones have recently been studied as photoinitiators of polymerization, and three different strategies have been developed to provide access to these structures. Notably, chalcones can be easily obtained by means of a Claisen-Schmidt condensation between an aldehyde and an acetophenone, in accordance with the reaction depicted in Scheme 1 [186][187][188][189][190][191][192][193][194][195]. No major differences can be found from the synthetic viewpoint between monoand bis-chalcones, except that two equivalents of aldehydes have to be used in the case of bis-chalcones, comprising a central cyclic ketone.…”

Recent advances on chalcone-based photoinitiators of polymerization

“…[166] From a synthetic viewpoint, chalcones can be prepared in one step, by condensation of an aldehyde on an acetophenone in various conditions. [167][168][169][170][171][172][173][174][175][176] Due to the easiness of synthesis, chalcones have been investigated in a wide range of applications, going from organogels [177] to organic light-emitting diodes, [178] organic photovoltaics [179,180]…”