The Synthesis and Biological Evaluation of 2-(1H-Indol-3-yl)quinazolin-4(3H)-One Derivatives

The treatment of many bacterial diseases remains a significant problem due to the increasing antibiotic resistance of their infectious agents. Among others, this is related to Staphylococcus aureus, especially methicillin-resistant S. aureus (MRSA) and Mycobacterium tuberculosis. In the present article, we report on antibacterial compounds with activity against both S. aureus and MRSA. A straightforward approach to 2-(1H-indol-3-yl)quinazolin-4(3H)-one and their analogues was developed. Their structural and functional relationships were also considered. The antimicrobial activity of the synthesized compounds against Mycobacterium tuberculosis H₃₇Rv, S. aureus ATCC 25923, MRSA ATCC 43300, Candida albicans ATCC 10231, and their role in the inhibition of the biofilm formation of S. aureus were reported. 2-(5-Iodo-1H-indol-3-yl)quinazolin-4(3H)-one (3k) showed a low minimum inhibitory concentration (MIC) of 0.98 μg/mL against MRSA. The synthesized compounds were assessed via molecular docking for their ability to bind long RSH (RelA/SpoT homolog) proteins using mycobacterial and streptococcal (p)ppGpp synthetase structures as models. The cytotoxic activity of some synthesized compounds was studied. Compounds 3c, f, g, k, r, and 3z displayed significant antiproliferative activities against all the cancer cell lines tested. Indolylquinazolinones 3b, 3e, and 3g showed a preferential suppression of the growth of rapidly dividing A549 cells compared to slower growing fibroblasts of non-tumor etiology.

Designing a new method for growing metal-organic framework (MOF) on MOF: synthesis, characterization and catalytic applications

Metal-organic frameworks as a unique class of high-surface-area materials have gained considerable attention due to their characteristic properties. In this perspective, herein, we report an eco-friendly and inexpensive route for the synthesis of 4(3H)-quinazolinones using magnetically separable core-shell-like bimetallic Fe₃O₄-MAA@Co-MOF@Cu-MOF NPs as environmentally-friendly heterogeneous catalysts. To the best of our knowledge, this is the first example of the integration of two different types of MOFs, which contain two different metal ions (Co²⁺ in the core and Cu²⁺ in the shell) using an external ligand. Our study not only introduces a novel nanostructured catalyst for the organic reaction but also presents a new strategy for the combination of two MOFs in one particle at the nanometer level. To survey the structural and compositional features of the synthesized nanocatalyst, a variety of spectroscopic and microscopic techniques including FT-IR, XRD, BET, TEM, HR-TEM, FE-SEM, EDX, EDX-mapping, TGA, VSM, and ICP-OES were employed. The combination of magnetic Co-MOF with Cu-MOF leads to achieving unique structural and compositional properties for Fe₃O₄-MAA@Co-MOF@Cu-MOF NPs with a particle size of 20-70 nm, mesostructure, and relatively large specific surface area (236.16 m² g^-1). The as-prepared nanostructured catalyst can be an excellent environment catalyst for the synthesis of a wide library of 4(3H)-quinazolinones derivatives, including electron-donating and electron-withdrawing aromatic, heteroaromatic, and aliphatic compounds under solvent-free conditions much better than the parent precursors. Moreover, by investigating the longevity of the nanocatalyst, the conclusion could be derived that the aforesaid nanocatalyst is stable under reaction conditions and could be recycled for at least seven recycle runs without a discernible decrease in its catalytic activity.

Wang resin catalysed sonochemical synthesis of pyrazolo[4,3-d]pyrimidinones and 2,3-dihydroquinazolin-4(1H)-ones: Identification of chorismate mutase inhibitors having effects on Mycobacterium tuberculosis cell viability

The enzyme chorismate mutase (or CM that is vital for the survival of bacteria) is an interesting pharmacological target for the identification of new anti-tubercular agents. The 5,5-disibstituted pyrazolo[4,3-d]pyrimidinone derivatives containing the fragment based on 4-amino-1-methyl-3-propyl-1H-pyrazole-5-carboxamide were designed and explored as the potential inhibitors of chorismate mutase. Based on encouraging docking results of two representative molecules evaluated in silico against MtbCM (PDB: 2FP2) the Wang resin catalysed sonochemical synthesis of target N-heteroarenes were undertaken. The methodology involved the reaction of 4-amino-1-methyl-3-propyl-1H-pyrazole-5-carboxamide with the appropriate cyclic/acyclic ketones to afford the desired products in acceptable (51-94%) yields. The methodology was also extended successfully towards the synthesis of 2,2-disubstituted 2,3-dihydroquinazolin-4(1H)-ones in excellent (85-90%) yields. In vitro MTT assay against the RAW 264.7 cell line followed by enzymatic assay against MtbCM identified 3b and 3c as active compounds that showed two H-bonding via their NH (at position 6) and CO group with MtbCM in silico and encouraging (54-57%) inhibition at 30 µM in vitro. Notably, none of the 2,2-disubstituted 2,3-dihydroquinazolin-4(1H)-ones showed any significant inhibition of MtbCM suggesting the favourable role of the pyrazole moiety in case of pyrazolo[4,3-d]pyrimidinones. The favourable role of cyclopentyl ring attached to the pyrazolo[4,3-d]pyrimidinone moiety and that of two methyl groups in place of cyclopentyl ring was also indicated by the SAR study. Besides showing effects against MtbCM in the concentration response study, 3b and 3c showed little or no effects on mammalian cell viability up to 100 µM in an MTT assay but decreased the % Mtb cell viability at 10-30 µM with > 20% decrease at 30 µM in an Alamar Blue Assay. Moreover, no adverse effects were noted for these compounds when tested for teratogenicity and hepatotoxicity in zebrafish at various concentrations. Overall, being the only example of MtbCM inhibitors that showed effects on Mtb cell viability the compound 3b and 3c are of further interest form the view point of discovery and development of new anti-tubercular agents.

Synthesis of a Pyrrolo[1,2-a]quinazoline-1,5-dione Derivative by Mechanochemical Double Cyclocondensation Cascade

N-heterocyclic compounds, such as quinazolinone derivatives, have significant biological activities. Nowadays, as the demand for environmentally benign, sustainable processes increases, the application of compounds from renewable sources, easily separable heterogeneous catalysts and efficient, alternative activation methods is of great importance. In this study, we have developed a convenient, green procedure for the preparation of 3a-methyl-2,3,3a,4-tetrahydropyrrolo[1,2-a]quinazoline-1,5-dione through a double cyclocondensation cascade using anthranilamide and ethyl levulinate. Screening of various heterogeneous Brønsted acid catalysts showed that Amberlyst^® 15 is a convenient choice. By applying mechanochemical activation in the preparation of this N-heterotricyclic compound for the first time, it was possible to shorten the necessary time to three hours compared to the 24 h needed under conventional conditions to obtain a high yield of the target product.

Prospect of DFT Utilization in Polymer-Graphene Composites for Electromagnetic Interference Shielding Application: A Review

The improvement in current materials science has prompted a developing need to capture the peculiarities that determine the properties of materials and how they are processed on an atomistic level. Quantum mechanics laws control the interface among atoms and electrons; thus, exact and proficient techniques for fixing the major quantum-mechanical conditions for complex many-particle, many-electron frameworks should be created. Density functional theory (DFT) marks an unequivocal advance in these endeavours. DFT has had a rapid influence on quintessential and industrial research during the last decade. The DFT system describes periodic structural systems of 2D or 3D electronics with the utilization of Bloch’s theorem in the direction of Kohn–Sham wavefunctions for the significant facilitation of these schemes. This article introduces and discusses the infinite systems modelling approach required for graphene-based polymer composites or their hybrids. Aiming to understand electronic structure computations as per physics, the impressions of band structures and atomic structure envisioned along with orbital predicted density states are beneficial. Convergence facets coupled with the basic functions number and the k-points number are necessary to explain for every physicochemical characteristic in these materials. Proper utilization of DFT in graphene-based polymer composites for materials in EMI SE presents the potential of taking this niche to unprecedented heights within the next decades. The application of this system in graphene-based composites by researchers, along with their performance, is reviewed.

Synthesis of Flavanone and Quinazolinone Derivatives from the Ruthenium-Catalyzed Deaminative Coupling Reaction of 2'-Hydroxyaryl Ketones and 2-Aminobenzamides with Simple Amines

The cationic Ru-H complex [(C₆H₆)(PCy₃)(CO)RuH]⁺BF₄^- (1) with 3,4,5,6-tetrachloro-1,2-benzoquinone (L1) was found to be a highly effective catalyst for the deaminative coupling reaction of 2'-hydroxyaryl ketones with simple amines to form 3-substituted flavanone products. The analogous deaminative coupling reaction of 2-aminobenzamides with branched amines directly formed 3,3-disubstituted quinazolinone products. The catalytic method efficiently installs synthetically useful flavanone and quinazolinone core structures without employing any reactive reagents.

Iodine-mediated electrochemical C(sp3)-H cyclization: the synthesis of quinazolinone-fused N-heterocycles

An efficient iodine-mediated electrochemical C(sp³)-H cyclization was developed under mild conditions. A variety of functionalized quinazolinone-fused N-heterocycles can be obtained with good to excellent yields by virtue of this method. The reaction features a broad substrate scope and scalability, and is metal-free and chemical oxidant-free.

Probing the catalytic activity of highly efficient sulfonic acid fabricated cobalt ferrite magnetic nanoparticles for the clean and scalable synthesis of dihydro, spiro and bis quinazolinones

An exceptionally productive, rapid, simple, and eco-friendly approach for the synthesis of 2,3-dihydroquinazolin-4(1H)-one has been developed utilizing acidic magnetically retrievable cobalt ferrite nanoparticles (CFNP@SO3H).

Bio-reduction of Graphene Oxide: Catalytic Applications of (Reduced) GO in Organic Synthesis

This work is based on various bio-reduction of graphene oxide into reduced graphene oxide and their applications in organic synthesis and group transformations. Graphene oxide, with abundant oxygencontaining functional groups on its basal plane, provides potential advantages, including excellent dispersibility in solvents and the good heterogeneous catalyst. This manuscript reviews various methods of synthesis of graphene and graphene oxide and a comparative study on their advantages and disadvantages, how to overcome disadvantages and covers extensive relevant literature review. In the last few years, investigation based on replacing the chemical reduction methods by some bio-compatible, chemical/impurity-free rGO including flash photo reductions, hydrothermal dehydration, solvothermal reduction, electrochemical approach, microwave-assisted reductions, light and radiation-induced reductions has been reported. Particularly, plant extracts have been applied significantly as an efficient reducing agent due to their huge bioavailability and low cost for bio-reduction of graphene oxide. These plant extracts mainly contain polyphenolic compounds, which readily get oxidized to the corresponding unreactive quinone form, which are the driving force for choosing them as bio-compatible catalyst. Currently, efforts are being made to develop biocompatible methods for the reduction of graphene oxide. The reduction abilities of such phytochemicals have been reported in the synthesis and stabilization of various nanoparticles viz. Ag, Au, Fe and Pd. Various part of plant extract has been applied for the green reduction of graphene oxide. Furthermore, the manuscript describes the catalytic applications of graphene oxide and reduced graphene oxide nanosheets as efficient carbo-catalysts for valuable organic transformations. Herein, important works dedicated to exploring graphene-based materials as carbocatalysts, including GO and rGO for organic synthesis including various functional group transformations, oxidation, reduction, coupling reaction and a wide number of multicomponent reactions have been highlighted. Finally, the aim of this study is to provide an outlook on future trends and perspectives for graphene-based materials in metal-free carbo-catalysis in green synthesis of various pharmaceutically important moieties.

Larvicidal Activities of 2-Aryl-2,3-Dihydroquinazolin -4-ones against Malaria Vector Anopheles arabiensis, In Silico ADMET Prediction and Molecular Target Investigation

Malaria, affecting all continents, remains one of the life-threatening diseases introduced by parasites that are transmitted to humans through the bites of infected Anopheles mosquitoes. Although insecticides are currently used to reduce malaria transmission, their safety concern for living systems, as well as the environment, is a growing problem. Therefore, the discovery of novel, less toxic, and environmentally safe molecules to effectively combat the control of these vectors is in high demand. In order to identify new potential larvicidal agents, a series of 2-aryl-1,2-dihydroquinazolin-4-one derivatives were synthesized and evaluated for their larvicidal activity against Anopheles arabiensis. The in silico absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties of the compounds were also investigated and most of the derivatives possessed a favorable ADMET profile. Computational modeling studies of the title compounds demonstrated a favorable binding interaction against the acetylcholinesterase enzyme molecular target. Thus, 2-aryl-1,2-dihydroquinazolin-4-ones were identified as a novel class of Anopheles arabiensis insecticides which can be used as lead molecules for the further development of more potent and safer larvicidal agents for treating malaria.

Facile One-Pot Friedlander Synthesis of Functionalized Quinolines using Graphene Oxide Carbocatalyst

BACKGROUND

Quinolines represent an important class of bioactive molecules which are present in various synthetic drugs, biologically active natural compounds and pharmaceuticals. Quinolines find their potential applications in various chemical and biomedical fields. Thereby, the demand for more efficient and simple methodologies for the synthesis of quinolines is growing rapidly.

OBJECTIVE

The green one-pot Friedlander Synthesis of Functionalized Quinolines has been demonstrated by using graphene oxide as a carbocatalyst.

METHOD

The graphene oxide catalyzed condensation reaction of 2-aminoaryl carbonyl compounds with different cyclic/ acyclic/ aromatic carbonyl compounds in methanol at 70°C affords different quinoline derivatives.

RESULTS

The reaction has been examined in different protic and aprotic solvents and the best yield of quinoline is observed in methanol at 70°C.

CONCLUSION

The present method of quinoline synthesis offers various advantages over other reported methods such as short reaction time, high yield of product, recycling of catalyst and simple separation procedure. The graphene oxide carbocatalyst can be easily recovered from the reaction mixture by centrifugation and then can be reused several times without any significant loss in its activity.

Boosting Enantioselectivity of Chiral Organocatalysts with Ultrathin Two-Dimensional Metal-Organic Framework Nanosheets

The development of methodologies for inducing and tailoring enantioselectivities of catalysts is an important issue in asymmetric catalysis. In this work, we demonstrate for the first time that chiral molecular catalysts can be boosted from completely nonselective to highly enantioselective when installed in nanostructured metal-organic frameworks (MOFs). Exfoliation of layered crystals is one of the most direct synthetic routes to unltrathin nanosheets, but its use in MOFs is limited by the availability of layered MOFs. We illustrate that layered MOFs can be designed using ligand-capped metal clusters and angular organic linkers. This leads to the synthesis of two three-dimensional (3D) layered porous MOFs from Zn₄-p-tert-butylsulfonyl calix[4]arene and chiral angular 1,1'-binaphthol/-biphenol dicarboxylic acids, which can be ultrasonic exfoliated into one- and two-layer nanosheets. The obtained MOF materials are efficient catalysts for asymmetric cascade condensation and cyclization of 2-aminobenzamide and aldehydes to produce 2,3-dihyroquinazolinones. While both binaphthol and biphenol display no enantioselectivity, restriction of their freedom in the MOFs leads to 56-90% and 46-72% ee, respectively, which are increased to 72-94% and 64-82% ee after exposure to external surfaces of the flexible nanosheets. Moreover, the MOF crystals and nanosheets exhibit highly sensitive fluorescent enhancement in the presence of chiral amino alcohols with enantioselectivity factors being, respectively, increased up to 1.4 and 2.3 times of the values of the diols, allowing them to be utilized in chiral sensing. Therefore, the observed enantioselectivities increase in the order organocatalyst < MOF crystals < MOF nanosheets in both catalysis and sensing. This work not only provides a strategy to make 3D layered MOFs and their untrathin nanosheets but also paves the way to utilize nanostructured MOFs to manipulate enantioselectivities of molecular catalysts.

Emerging Trends in the Syntheses of Heterocycles Using Graphene-based Carbocatalysts: An Update

Graphene-based carbocatalysts owing to numerous amazing properties such as large specific surface area, high intrinsic mobility, excellent thermal and electrical conductivities, chemical stability, ease of functionalization, simple method of preparation, effortless recovery and recyclability have gained a superior position amongst the conventional homogeneous and heterogeneous catalysts. In this review, an endeavor has been made to highlight the syntheses of diverse heterocyclic compounds catalyzed by graphene-based catalysts. Further, the study also reveals that all the catalysts could be reused several times without significant loss in their catalytic activity. Additionally, most of the reactions catalyzed by graphene-based carbocatalysts were carried out at ambient temperature and under solvent-free conditions. Thus, the graphene-based catalysts do not merely act as efficient catalysts but also serve as sustainable, green catalysts. This review is divided into various sub-sections, each of which comprehensively describes the preparation of a particular heterocyclic scaffold catalyzed by graphene-derived carbocatalyst in addition to synthesis of graphene oxide and reduced graphene oxide, functionalization, and structural features governing their catalytic properties. Synthesis of heterocycles catalyzed by graphene-based carbocatalysts.

Adjusting the Structure and Electronic Properties of Carbons for Metal-Free Carbocatalysis of Organic Transformations

Carbon nanomaterials doped with some other lightweight elements were recently described as powerful, heterogeneous, metal-free organocatalysts, adding to their high performance in electrocatalysis. Here, recent observations in traditional catalysis are reviewed, and the underlying reaction mechanisms of the catalyzed organic transformations are explored. In some cases, these are due to specific active functional sites, but more generally the catalytic activity relates to collective properties of the conjugated nanocarbon frameworks and the electron transfer from and to the catalytic centers and substrates. It is shown that the learnings are tightly related to those of electrocatalysis; i.e., the search for better electrocatalysts also improves chemocatalysis, and vice versa. Carbon-carbon heterojunction effects and some perspectives on future possibilities are discussed at the end.

High acidity cellulose sulfuric acid from sulfur trioxide: a highly efficient catalyst for the one step synthesis of xanthene and dihydroquinazolinone derivatives

A cellulose sulfonate catalyst (HS-cellulose sulfonate) with high stability, excellent catalytic activity and high acidity value (about 1.55 mmol g⁻¹) was successfully prepared by SO₃ gas phase sulfonation. The basic morphology and nanostructure of the catalyst were determined by HRTEM, XRD, IR, TG, etc. In addition, the catalyst was applied to the catalytic reaction of a dihydroquinazolinone derivative and a xanthene compound, and very valuable results were obtained. The development and preparation of cellulose sulfonate catalysts provide a good approach for the development and application of cellulose, and also an important application of green organic catalytic synthesis methodology.

The HS-cellulose sulfonate catalysed green and efficient one-step synthesis of xanthene and dihydroquinazolinone derivatives.

Bismuth-Catalyzed Synthesis of 2-Substituted Quinazolinones

The bismuth-catalyzed oxidative condensation of aldehydes with 2-aminobenzamide under aerobic conditions is reported using ethanol as the solvent. Good to excellent isolated yields (68-95%) of the corresponding 2-substituted quinazolinones were obtained under mild reaction conditions with excellent functional group tolerance. The quinazolinones were further functionalized to afford N-allylated quinazolinones, 2-aminopyridine derivatives, and annulated polyheterocyclic compounds via transition-metal catalyzed reactions.

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.

Palladium-catalyzed oxidative CC bond cleavage with molecular oxygen: one-pot synthesis of quinazolinones from 2-amino benzamides and alkenes

Palladium-catalyzed oxidative cleavage/cyclization has been disclosed for the concise synthesis of various quinazolinone derivatives from readily available 2-aminobenzamides and terminal alkenes with excellent functional group tolerance.

Probing Carbocatalytic Activity of Carbon Nanodots for the Synthesis of Biologically Active Dihydro/Spiro/Glyco Quinazolinones and Aza-Michael Adducts

Herein, we report the fluorescent carbon dots as an effective and recyclable carbocatalyst for the generation of carbon-heteroatom bond leading to quinazolinone derivatives and aza-Michael adducts under mild reaction conditions. The results establish this nanoscale form of carbon as an alternative carbocatalyst for important acid catalyzed organic transformations. The mild surface acidity of carbon dots imparted by -COOH functionality could effectively catalyze the formation of synthetically challenging spiro/glycoquinazolinones under the present reaction conditions.

Crosslinked chitosan nanoparticle-anchored magnetic multi-wall carbon nanotubes: a bio-nanoreactor with extremely high activity toward click-multi-component reactions

In the present study, we have designed a procedure for the synthesis of a bio-nanoreactor catalyst, crosslinked chitosan nanoparticle-anchored magnetic multi-wall carbon nanotubes (CS NPs/MWCNT@Fe₃O₄), via an in situ ionotropic gelation method.

Active sites on graphene-based materials as metal-free catalysts

Defects, periphery, heteroatoms and heterojunctions can make graphene behave as a catalyst without the need for metallic elements.

Facile and eco-friendly synthesis of chromeno[4,3-b]pyrrol-4(1H)-one derivatives applying magnetically recoverable nano crystalline CuFe2O4 involving a domino three-component reaction in aqueous media

Nanocrystalline CuFe₂O₄ catalyzed one pot three component synthesis of chromeno[4,3-b]pyrrol-4(1H)-one derivatives has been achieved in aqueous media.

Iron nitrate/TEMPO-catalyzed aerobic oxidative synthesis of quinazolinones from alcohols and 2-aminobenzamides with air as the oxidant

A highly efficient, one-pot Fe(NO₃)₃/TEMPO-catalyzed protocol for aerobic oxidative synthesis of quinazolinones from easily accessible primary alcohols and 2-aminobenzamides with molecular oxygen as the terminal oxidant.

Practical carbocatalysis by graphene oxide nanosheets in aqueous medium towards the synthesis of diversified dibenzo[1,4]diazepine scaffolds

Metal free green protocol in aqueous medium. Use of GO nanosheets as exclusive heterogeneous catalyst. Almost intact catalytic activity upto the 5th run. Mild reaction conditions preserve sensitive structural moeities.