Comprehensive methodologies for synthesizing tricyclic fused pyrimidoquinolines of biological relevance: a review

Among quinoline-fused heterocycles, tricyclic pyrimidoquinoline nuclei have received considerable attention from synthetic chemists and medicinal and materials scientists over many years because they occur commonly in various biologically important natural products and potent drugs that exhibit anticancer, antibacterial, anti-inflammatory, antilipidemic, antioxidant and antimalarial activities. This study will be beneficial for medicinal chemists in the field of drug discovery to synthesize new fused tricyclic pyrimidoquinolines as potent therapeutic agents. This review provides a comprehensive compilation of the methodologies developed for the synthesis of all six known types of pyrimidoquinolines reported thus far. This article includes synthesis via solvent-free reactions, Vilsmeier-Haack reaction, Lewis and Brønsted acid catalysis, Pictet-Spengler reaction, the use of metal oxide nanoparticles as a green catalyst, multicomponent reactions (MCR), the use of l-proline as an environmentally friendly organocatalyst, aza-Wittig reaction, the use of β-cyclodextrin (β-CD) as a supramolecular catalyst, ultrasound irradiation, microwave-assisted reaction and ultraviolet light (UV365) irradiation. To the best of our knowledge, this is the first review that focuses on the synthesis of all six types of pyrimidoquinolines along with mechanistic aspects. Some medicinal applications are also mentioned.

Synthesis of Pyrimido[4, 5-b]quinolones from 6-Aminopyrimidin-4- (thi)one Derivatives (Part I)

Abstract:

Quinoline and pyrimidine are well-known moieties, which appear in various natural and synthetic products. Furthermore, quinoline-pyrimidine-inspired hybrids are known to have several biological properties. In addition, many pyrimido[4,5-b]quinolinone ring systems, specifically concerning medicinal chemistry, have been reported over the past decade. This review depicts the synthesis of pyrimido[4, 5-b] quinolones (PyQs4,5-b) through 6-aminopyrimidin-4-(thi)one derivatives. The preparation of PyQs4,5-b was clarified through the following chemical reactions: Vilsmeier-Haack formylation, Hantzsch-like reaction, and one-pot three-component reaction.

[Msim]CuCl3: as an efficient catalyst for the preparation of 5-amino-1H-pyrazole-4-carbonitriles by anomeric based oxidation

3-Methyl-1-sulfonic acid imidazolium trichlorido copper (II) {[Msim]CuCl3} was prepared and used as a new catalyst for the preparation of 5-amino-1H-pyrazole-4-carbonitriles. In this reaction, the pyrazole ring was formed by an anomeric and vinylogous anomeric effect in the structure of the product.

Agar-entrapped sulfonated DABCO: Agelly acidic catalyst for the acceleration of one-pot synthesis of 1,2,4-triazoloquinazolinone and some pyrimidine derivatives

In this project, a recently synthesized DABCO-based catalyst is entrapped in agar to reduce its moisture sensitivity leading to enhancement of its stability and catalytic activity. After preparation and identification this new reagent is used as an efficient and environmentally safe catalyst for the preparation of 1, 2, 4-triazoloquinazolinone and some pyrimidine derivatives. This method is accompanied with some superiorities such as, simple operation, mild and green conditions, use of low cost and non-hazardous natural material, short reaction times, easy preparation methods and simple work-up procedures. The prepared catalyst can be re-used for several times in all of the studied reactions without any appreciable loss in its activity.

A novel organic–inorganic hybrid material: production, characterization and catalytic performance for the reaction of arylaldehydes, dimedone and 6-amino-1,3-dimethyluracil

A novel silica-based organic–inorganic hybrid catalyst was prepared, characterized and applied for the synthesis of pyrimido[4,5-b]quinolines.

Green recipes to quinoline: A review

The quinoline core possesses a vast number of biological activities such as anticancer, antimalarial, antimicrobial, antifungal, antitubercular and antileishmanial. The conventional classical synthetic methods require the use of expensive and harsh conditions such as high temperature. Currently the scientific communities are searching new methodology to eliminate the use of chemicals, solvents and catalysts, which are hazardous to human health as well as to environment. This review provides a concise overview of new dimensions of green chemistry approaches in designing quinoline scaffold that would encourage the researchers towards green chemistry as well as future application of these greener, non-toxic, environment friendly methods in designing quinoline scaffold.

A One-Pot, Three-Component, Solvent-Free Synthesis of Novel 6H-Chromeno[3’,4’:5,6]Pyrido[2,3-d]Pyrimidine-Triones under Microwave Irradiation

A green and efficient method for preparing novel heterocyclic systems is established through the reaction of differently substituted benzaldehydes, barbituric acid and 4-amino-2H-chromene-2-one under solvent-free conditions. This method affords 6H-chromeno[3’,4’:5,6] pyrido[2,3-d]pyrimidine-trione derivatives in high yields and short reaction times.

An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes

This review article discusses the progress related to the synthesis and catalytic applications of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials for industrial and laboratory products. These catalysts are widely used in acid-catalyzed processes. Most of these acid catalysts are eco-friendly, reusable, and stable. Moreover, the discovery of unique catalysts is vital for developing new, efficient, and reusable catalysts for industrial and laboratory applications. The aim of this review article is to review the recent studies (2014-2018) in the field of the utility of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials for developing acidic catalysts.

DABCO-based ionic liquids: green and recyclable catalysts for the synthesis of barbituric and thiobarbituric acid derivatives in aqueous media

A new and straightforward method for the synthesis of 5-arylidine barbituric and thiobarbituric acids through a reaction between barbituric acid and its thio-analogue with aldehydes using [DABCO](SO₃H)₂(HSO₄)₂) as an efficient catalyst has been reported.