One-Pot Three-Component Synthesis of 2,3-Dihydroquinazolin-4(1H)-Ones in the Presence of a Molecular Sieve Supported Lanthanum Catalyst

Organocatalyzed Heterocyclic Transformations In Green Media: A Review

Background:

Since the discovery of metal-free catalysts or organocatalysts about twenty years ago, a number of small molecules with different structures have been used to accelerate organic transformations. With the development of environmental awareness, to obtain highly efficient scaffolds, scientists have directed their studies towards synthetic methodologies that minimize or preferably eliminate the formation of waste, avoid toxic solvents and reagents and use renewable starting materials as far as possible.

Methods:

In this connection, the organocatalytic reactions providing efficiency and selectivity for most of the transformations have become an endless topic in organic chemistry since several advantages from both practical and environmental standpoints. Organocatalysts contributing to the transformation of reactants into products with the least possible waste production, have been serving the concept of green chemistry.

Results and Conclusion:

Organocatalysts have been classified based on their binding capacity to the substrate with covalent or noncovalent interactions involving hydrogen bonding and electrostatic interaction. Diverse types of small organic compounds including proline and its derivatives, phase-transfer catalysts, (thio)urease, phosphoric acids, sulfones, N-oxides, guanidines, cinchona derivatives, aminoindanol, and amino acids have been utilized as hydrogen bonding organocatalysts in different chemical transformations.

Palladium(II) on 4 Å Molecular Sieves: A Simple and Reusable Catalyst for the Preparation of Ynones

Abstract

Pd2+ on 4 Å molecular sieves support has been prepared and investigated. The catalyst has successfully been used in the reaction of acyl chlorides and terminal alkynes yielding ynones. The catalyst can be reused without significant loss of activity.

Graphic Abstract

The Application of 4Å Molecular Sieves in Organic Chemical Syntheses: An Overview

In the last two decades, considerable attention has been devoted to the use of 4Å molecular sieves (MS 4A) in organic chemical syntheses. Initially, they were applied as drying agents in order to dry gases, solvents and liquid reagents. Nowadays, there is a growing tendency to apply MS 4A as an additive, catalyst, co-catalyst or catalyst support in organic reactions. In this review, we aim to summarize the recent examples of organic syntheses promoted by MS 4A from 1997 to 2020. We hope to provide the reader with an overview of the potential of MS 4A in the field of organic synthesis.

1 Introduction

2 Application as an Additive

3 Application as Catalyst

4 Application as Co-catalyst

5 Application as Support

6 Conclusion

Synthesis, characterization, and investigation of the anti-inflammatory effect of 2,3-disubstituted quinazoline-4(1H)-one

Background

Quinazolin-4(1H)-one nucleus has attracted the attention of medicinal chemists due to their clinical uses. Modification of quinazolinone ring for the development of pharmaceutical and clinical compound for its anti-inflammatory potential.

Results

In vitro anti-inflammatory activity of the synthesized compounds was performed by using egg albumin protein denaturation assay, while in vivo anti-inflammatory activity was performed by using carrageenan-induced rat paw edema and cotton pellet-induced granuloma pouch model.

In the present study, we synthesized a new series of 2,3-disubstituted quinazolin-4(1H)-one derivatives and evaluated their in vivo, in vitro anti-inflammatory effect. Their chemical structures are confirmed by FTIR, 1HNMR, and mass spectrum. Among all the synthesized compounds, G1 and G3 exhibit the significant anti-inflammatory activity by inhibiting release of inflammatory mediators like prostaglandin, histamine, and serotonin. in both in vivo and in vitro models as compared to compound G2.

Conclusion

These synthesized compounds showed anti-inflammatory activity by inhibiting prostaglandins and COX enzymes. So, all test compounds may be used for both inflammation as well as inflammation-induced cancer therapy. Future various screening method related with inflammation and inflammation-induced cancer needs to be evaluated pre-clinically and clinically.

Simple and efficient synthesis of 2,2′-arylmethylenebis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) derivatives

Abstract

A simple and efficient method for the synthesis of 2,2′-arylmethylenebis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) derivatives using 4 Å molecular sieves as catalyst is described. This approach offers several advantages such as high yields, mild reaction conditions, easily accessible, and reusable catalyst, and simple work-up procedure.

Graphic abstract

2,3-Dihydroquinazolin-4(1H)-one as a privileged scaffold in drug design

2,3-Dihydroquinazolin-4-one (DHQ) belongs to the class of nitrogen-containing heterocyclic compounds representing a core structural component in various biologically active compounds. In the past decades, several methodologies have been developed for the synthesis of the DHQ framework, especially the 2-substituted derivatives. Unfortunately, multistep syntheses, harsh reaction conditions, and the use of toxic reagents and solvents have limited their full potential as a versatile fragment. Recently, use of green chemistry and alternative strategies are being explored to prepare diverse DHQ derivatives. This fragment is used as a synthon for the preparation of biologically active quinazolinones and as a functional substrate for the synthesis of modified DHQ derivatives exhibiting different biological properties. In this review, we provide a comprehensive assessment of the synthesis and biological evaluations of DHQ derivatives.