Synthesis and Antioxidant Activity Evaluation of Some Novel Aminocarbonitrile Derivatives Incorporating Carbohydrate Moieties

FT-IR-based fingerprint combined with unsupervised chemometric analysis revealed particle sizes and aqueous-ethanol ratio alter the chemical composition and nutraceutical value of Daucus carota

This study reported the effects of particle size of dry powder and the optimum solvent extraction on the nutraceutical value of carrot by observing its FT-IR fingerprint, TPC, TFC, and antioxidant activity. The dried-powdered carrot was ultrasound-assisted extracted using EtOH, water, and EtOH-water. The TFC, TPC, and antioxidant activity were analysed by a colorimetric method using a spectrophotometry UV-Vis. The chemotaxonomy of samples was analysed using FT-IR combined with chemometrics analysis. The TFC, TPC, and antioxidant capacity were significantly different for each sample with the highest TFC, TPC, and antioxidant obtained on particle size 149 μm with EtOH-water (50:50) as the most prominent solvent (19.51 mgQE/g, 9.90 mgGAE/g, IC50: 16.7 ± 0.89 µg/mL). FT-IR profiling of samples also illustrates a minor different pattern of the spectrum, indicating there is a difference in their chemical composition. The particle size and EtOH-water ratio influence the chemical composition and antioxidant activity of carrots.

Modulation of Oxidative Stress and Neuroinflammation by Cannabidiol (CBD): Promising Targets for the Treatment of Alzheimer's Disease

Alzheimer's disease (AD) is a progressive neurodegenerative disease and the most common form of dementia globally. Although the direct cause of AD remains under debate, neuroinflammation and oxidative stress are critical components in its pathogenesis and progression. As a result, compounds like cannabidiol (CBD) are being increasingly investigated for their ability to provide antioxidant and anti-inflammatory neuroprotection. CBD is the primary non-psychotropic phytocannabinoid derived from Cannabis sativa. It has been found to provide beneficial outcomes in a variety of medical conditions and is gaining increasing attention for its potential therapeutic application in AD. CBD is not psychoactive and its lipophilic nature allows its rapid distribution throughout the body, including across the blood-brain barrier (BBB). CBD also possesses anti-inflammatory, antioxidant, and neuroprotective properties, making it a viable candidate for AD treatment. This review outlines CBD's mechanism of action, the role of oxidative stress and neuroinflammation in AD, and the effectiveness and limitations of CBD in preclinical models of AD.

Synthesis, anticancer activity and molecular docking of new quinolines, quinazolines and 1,2,4-triazoles with pyrido[2,3-d] pyrimidines

Recently, heterocyclic compounds such as pyrido [2,3-d] pyrimidinones, 1,2,4-triazolopyrimidines, pyrimidoquinazolines, and quinoline derivatives have gained attention from researchers due to their pharmacological and biological activities. To synthesize new compounds, quinoline-2-thioxopyrido [2,3-d] pyrimidinone (1) and methylthioquinoline-pyrido [2,3-d] pyrimidinones (2) were used as starting materials. The new compounds synthesized were quinoline-pyrido [2,3-d] (DeGoey et al., 2013; Gouda et al., 2020; Dangolani et al., 2018) [1, 2,4]triazolopyrimidinones (5a-d), 2-methylsulfonyl-quinoline-pyrido [2,3-d]pyrimidinone (6), pyrido [2,3-d]pyrimidine derivatives, pyridopyrimido (Gouda et al., 2020; DeGoey et al., 2013) 2,12,1-b] quinazoline (9), pyrido [(Khajouei et al., 2021; Gouda et al., 2020) 3,23,2-e]bis (1,2,4-triazole)pyrimidine (12a,b) and pyridopyrimido-diquinazoline-dione (16) derivatives. These compounds were synthesized with high efficiency, producing yields ranging from 69% to 90%, under moderate conditions, through treating (2) or (10) with various reagents such as anthranilic acid, phosphorus oxychloride, hydrazine hydrate, formic acid, glacial acetic acid, arylamine (aniline, 4-chloroaniline, or 4-methoxyaniline), and sec-amine (piperazine or morpholine). The new structures of the synthesized compounds were verified using various spectroscopic procedures, such as IR, NMR, and mass spectra. Molecular docking studies were carried out to investigate and discuss how the prepared compounds bind to amino acids such as Estrogen Receptor alpha, EGFR, and NADPH oxidase protein. Also, the synthesized products were tested for their anticancer and antioxidant activities against the (MCF-7) breast carcinoma cell line and human normal Retina pigmented epithelium cells (RPE-1). The study on the structure-activity relationship (SAR) established a correlation between the chemical structure of the newly synthesized compounds and their anticancer activity. The findings suggest that compounds 5a-d, 9,12a-b, and 16 exhibited promising anticancer activity and antioxidant effects as measured by DPPH inhibition.

Synthesis of novel rapanone derivatives via organocatalytic reductive C-alkylation: biological evaluation of antioxidant properties, in vivo zebrafish embryo toxicity, and docking studies

A biologically crucial natural product rapanone 1 was isolated from Embelia ribes at the gram scale with excellent purity. Semi-synthetic analogs of 1 semi-synthesized through reductive C-alkylation could increase the therapeutic value of the compounds. Herein, a new synthetic methodology was developed as a single-step reductive C-alkylation protocol using a metal-free, room-temperature-based reaction condition that can be scaled up to gram-scale synthesis with an excellent yield of up to 93%. A straightforward purification protocol was employed for the product obtained by this method. The derivatives of 1 showed antioxidant activity, which was evaluated using DPPH and ABTS scavenging assays. Compounds 5a-5ze showed an IC50 value of 2.48-3.37 μM and 1.81-3.12 μM. Substitution by electron-donating groups on the quinone moiety seems to play an essential role in the increased antioxidant activity of compounds 5a-5i, 5v, 5w, 5zc, and 5z. Further, the in vivo embryotoxicity of 1 and its derivatives was analyzed in a zebrafish-based aquatic toxicology model. Zebrafish embryos were exposed to 1 and 5a-5ze at 20 to 160 μM concentrations. They showed reduced toxicity and a survival rate of 90-98% after 96 hpf of treatment; similarly, the compounds 5a-5i, 5v, 5w, 5zc, and 5zd did not significantly affect the hatching rates of 75.66-85.33% or developmental abnormalities of the embryos after 48 hpf of treatment. In silico molecular docking studies for the parent compound, along with its derivatives 5a-5i, 5v-5w, 5zc-5zd, and standard l-ascorbic acid (l-Aa) indicated favorable interactions with the active site of the crystal structure, coupled with the assay protein PDB:1ZB6, which was responsible for the observed biological understanding and potential.

Copper-Catalyzed Enantioselective Formal [4 + 1] and [3 + 3] Cycloaddition of Ethynylethylene Carbonates

Herein we employed ethynylethylene carbonates (EECs) to achieve formal [4 + 1] and [3 + 3] cycloaddition with cyclic 1,3-dicarbonyl compounds. On one hand, EECs with styryl substitution could undergo a remotely controlled enantioselective [4 + 1] cycloaddition reaction. This reaction exhibits good chemoselectivity, regioselectivity, and enantioselectivity. In addition, a [3 + 3] cycloaddition reaction of EECs with cyclic 1,3-dicarbonyl compounds was also achieved, leading to a series of 4H-pyrans with impressive chemoselectivity and enantioselectivity.

Synthesis, design, and antimicrobial activity of pyrido[2,3‐d][1,2,4]triazolo[4,3‐a]pyrimidinones based on quinoline derivatives

The pyrido[2,3‐d]pyrimidine moieties are one of the most biologically widespread heterocyclic compounds as antimicrobial, antioxidant, antitubercular, antiviral and anti‐inflammatory. Hence, we synthesized an efficient new series of 2‐thioxo‐pyrido[2,3‐d]pyrimidinone, 2‐hydrazinyl‐(quinolin‐2‐yl)pyrido[2,3‐d]pyrimidinone,N′‐(quinolin‐2‐yl)‐pyrido[2,3‐d]pyrimidine‐(formo/aceto)‐hydrazide and substituted‐(quinolin‐2‐yl)pyrido[2,3‐d][1,2,4]triazolo[4,3‐a]pyrimidinone derivatives. The characterization of new compounds was corresponded by using spectroscopic techniques, IR, NMR and Mass spectra. In vitro, all compounds were evaluated as antimicrobial activity compared with cefotaxime sodium and nystatin as the standard drug. This work deals with the exploration of the new heterocyclic compounds and medicinal diversity of quinoline‐pyrido[2,3‐d][1,2,4]triazolo[4,3‐a]pyrimidine derivatives that might pave the way for long in the discovery of therapeutic medicine for future drug design.

Novel Pyrimidine Derivatives as Antioxidant and Anticancer Agents: Design, Synthesis and Molecular Modeling Studies

The heterocyclic ring system of pyrido [2,3-d]pyrimidines is a privileged scaffold in medicinal chemistry, possessing several biological activities. The synthesis of the pyrimidine derivatives was performed via the condensation of a suitable α,β-unsaturated ketone with 4-amino-6-hydroxy-2-mercaptopyrimidine monohydrate in glacial acetic acid. Chalcones were synthesized, as starting materials, via the Claisen-Schmidt condensation of an appropriately substituted ketone and an appropriately substituted aldehyde in the presence of aqueous KOH 40% w/v in ethanol. All the synthesized compounds were characterized using IR, ¹H-NMR, ¹³C-NMR, LC-MS and elemental analysis. The synthesized compounds were evaluated for their antioxidant (DPPH assay), anti-lipid peroxidation (AAPH), anti-LOX activities and ability to interact with glutathione. The compounds do not interact significantly with DPPH but strongly inhibit lipid peroxidation. Pyrimidine derivatives 2a (IC₅₀ = 42 μΜ), 2f (IC₅₀ = 47.5 μΜ) and chalcone 1g (IC₅₀ = 17 μM) were the most potent lipoxygenase inhibitors. All the tested compounds were found to interact with glutathione, apart from 1h. Cell viability and cytotoxicity assays were performed with the HaCaT and A549 cell lines, respectively. In the MTT assay towards the HaCaT cell line, none of the compounds presented viability at 100 μM. On the contrary, in the MTT assay towards the A549 cell line, the tested compounds showed strong cytotoxicity at 100 μM, with derivative 2d presenting the strongest cytotoxic effects at the concentration of 50 μΜ.

Sugars in Multicomponent Reactions: A Toolbox for Diversity-Oriented Synthesis

Multicomponent reactions (MCRs) cover strategically employed chemical transformations that incorporate three or more reactants in one pot leading to a functionalized final product. Thus, it is an ideal tool to achieve high levels of complexity, diversity, yields of desired products, atom economy, and reduced reaction times. Sugars belong to the class of naturally occurring compounds with fascinating applications in the field of drug discovery due to the presence of various hydroxy groups and well-defined stereochemistry. However, their potential in MCRs has been realized only recently. This account describes recent advances in the synthesis of sugar-derived heterocycles synthesized by MCRs. We hope to encourage the synthetic and medicinal chemistry community to apply this powerful MCR chemistry to generate novel glycoconjugate challenges.

1 Introduction

2 Synthesis of Various Functionalized Sugar Compounds

2.1 Passerini and Ugi Multicomponent Reactions

2.2 Petasis Reaction

2.3 Hantzsch Reaction

2.4 Domino Ferrier–Povarov Reaction

2.5 Marckwald Reaction

2.6 Groebke–Blackburn–Bienaymé (GBB) Reaction

2.7 Prins–Ritter Reaction

2.8 Debus–Radziszewski Imidazole Synthesis Reaction

2.9 Mannich Reaction

2.10 A3-Coupling Reaction

2.11 [3+2]-Cycloaddition Reactions

2.12 Miscellaneous Reactions

3 Conclusion

Importance of Hybrid Catalysts toward the Synthesis of 5H-Pyrano[2,3-d]pyrimidine-2-ones/2,4-diones (Thiones)

The pyranopyrimidine core is a key precursor for medicinal and pharmaceutical industries due to its broader synthetic applications as well as its bioavailability. Among its four possible isomers, we found that 5H-pyrano[2,3-d]pyrimidine scaffolds have a wide range of applicability, and in recent years, they have been intensively investigated, but the development of the main core is found to be more challenging due to its structural existence. In this review article, we cover all of the synthetic pathways that are employed for the development of substituted 4-aryl-octahydropyrano/hexahydrofuro[2,3-d]pyrimidin-2-one (thiones) and 5-aryl-substituted pyrano[2,3-d]pyrimidindione (2-thiones) derivatives through a one-pot multicomponent reaction using diversified hybrid catalysts such as organocatalysts, metal catalysts, ionic liquid catalysts, nanocatalysts, green solvents, catalyst-/solvent-free conditions, and miscellaneous catalysts as well as the mechanism and recyclability of the catalysts. This review mainly focuses on the application of hybrid catalysts (from 1992 to 2022) for the synthesis of 5H-pyrano[2,3-d]pyrimidine scaffolds. This review will definitely attract the world's leading researchers to utilize broader catalytic applications for the development of lead molecules.

Catalyst-Free, Room-Temperature Accessible Regioselective Synthesis of Spiroquinolines and Their Antioxidant Study

An efficient, regioselective, and environmentally benign approach was established using the multicomponent reaction-based synthesis of novel antioxidant spiroquinoline derivatives such as spiro[dioxolo[4,5-g]quinoline], spiro[dioxino[2,3-g]quinoline], and spiro[pyrazolo[4,3-f]quinoline] by reaction of aryl aldehyde, Meldrum's acid, and amine derivatives under an additive-free reaction in aqueous ethanol. Here, two asymmetric carbon centers, three new C-C bonds, and one C-N bond are developed in the final motif. This synthetic methodology offers excellent yields with an easy workup procedure, high diastereoselectivity [d.r. >50:1 (cis/trans)], admirable atom economy, and low E-factor values. Synthesized spiro compounds were investigated for their in vitro antioxidant activity by 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assays. In the ABTS radical scavenging assay, compounds 4d, 4f, and 4l exhibit excellent potency, and in the DPPH radical scavenging assay, compounds 4a, 4d, 4f, and 4g, exhibit excellent potency.

Synthesis of 3,4-Dihydropyrimidin(thio)one Containing Scaffold: Biginelli-like Reactions

The interest in 3,4-dihydropyrimidine-2(1H)-(thio)ones is increasing every day, mainly due to their paramount biological relevance. The Biginelli reaction is the classical approach to reaching these scaffolds, although the product diversity suffers from some limitations. In order to overcome these restrictions, two main approaches have been devised. The first one involves the modification of the conventional components of the Biginelli reaction and the second one refers to the postmodification of the Biginelli products. Both strategies have been extensively revised in this manuscript. Regarding the first one, initially, the modification of one of the components was covered. Although examples of modifications of the three of them were described, by far the modification of the keto ester counterpart was the most popular approach, and a wide variety of different enolizable carbonylic compounds were used; moreover, changes in two or the three components were also described, broadening the substitution of the final dihydropyrimidines. Together with these modifications, the use of Biginelli adducts as a starting point for further modification was also a very useful strategy to decorate the final heterocyclic structure.

Insights into the recent progress in the medicinal chemistry of pyranopyrimidine analogs

Heterocycles containing the pyranopyrimidine motif have attracted the interest of researchers in recent decades due to their ability to synthesize and explore at a large scale to explore the biological diversity. Therefore, this review highlights the biological characteristics and synthetic approaches adopted to prepare pyranopyrimidine analogs in the last five years. Several novel preparation procedures have been summarized to synthesize these compounds using ionic, basic, or nanocatalysts or catalyst-free conditions to obtain these compounds in good yields. Pyranopyrimidines could also be used as ligands in the preparation of metal complexes with increased biological potency. The different sections include the antimicrobial, antitubercular, antimalarial, antiviral "SARS-CoV-2 inhibitors", antidiabetic, antitumor, cytotoxic, antiinflammatory, antioxidant, anticoagulant, urease inhibitory activities, and tyrosine inhibitors. The results are discussed based on the structure-activity relationships (SARs) and the mechanism of action.

Synthesis and Antimicrobial, Anticancer and Anti-Oxidant Activities of Novel 2,3-Dihydropyrido[2,3-d]pyrimidine-4-one and Pyrrolo[2,1-b][1,3]benzothiazole Derivatives via Microwave-Assisted Synthesis

In our attempt towards the synthesis and development of effective antimicrobial, anticancer and antioxidant agents, a novel series of 2,3-dihydropyrido[2,3-d]pyrimidin-4-one 7a–e and pyrrolo[2,1-b][1,3]benzothiazoles 9a–e were synthesized. The synthesis of 2-(1,3-benzo thiazol-2-yl)-3-(aryl)prop-2-enenitrile (5a–e) as the key intermediate was accomplished by a microwave efficient method. Via a new variety oriented synthetic microwave pathway, these highly functionalized building blocks allowed access to numerous fused heteroaromatic such as 7-amino-6-(1,3-benzo thiazol-2-yl)-5-(aryl)-2-thioxo-2,3dihydropyrido [2,3-d]pyrimidin-4(1H)-one 7a–e and 1-amino-2-(aryl)pyrrolo[2,1-b][1,3]benzothiazole-3-carbonitrile derivatives 9a–e in order to study their antimicrobial and anticancer activity. The present investigation offers effective and rapid new procedures for the synthesis of the newly polycondensed heterocyclic ring systems. All the newly synthesized compounds were evaluated for antimicrobial, anticancer and antioxidant activity. Compounds 7a,d, and 9a,d showed higher antimicrobial activity than cefotaxime and fluconazole while the remaining compounds exhibited good to moderate activity against bacteria and fungi. An anticancer evaluation of the newly synthesized compounds against the three tumor cell lines (lung cell NCI-H460, liver cancer HepG2 and colon cancer HCT-116) exhibited that compounds 7a, d, and 9a,d have higher cytotoxicity against the three human cell lines compared to doxorubicin as a reference drug. These compounds also exhibited higher antioxidant activity and a great ability to protect DNA from damage induced by bleomycin.

Naturally Occurring Antioxidant Therapy in Alzheimer’s Disease

It is estimated that the prevalence rate of Alzheimer’s disease (AD) will double by the year 2040. Although currently available treatments help with symptom management, they do not prevent, delay the progression of, or cure the disease. Interestingly, a shared characteristic of AD and other neurodegenerative diseases and disorders is oxidative stress. Despite profound evidence supporting the role of oxidative stress in the pathogenesis and progression of AD, none of the currently available treatment options address oxidative stress. Recently, attention has been placed on the use of antioxidants to mitigate the effects of oxidative stress in the central nervous system. In preclinical studies utilizing cellular and animal models, natural antioxidants showed therapeutic promise when administered alone or in combination with other compounds. More recently, the concept of combination antioxidant therapy has been explored as a novel approach to preventing and treating neurodegenerative conditions that present with oxidative stress as a contributing factor. In this review, the relationship between oxidative stress and AD pathology and the neuroprotective role of natural antioxidants from natural sources are discussed. Additionally, the therapeutic potential of natural antioxidants as preventatives and/or treatment for AD is examined, with special attention paid to natural antioxidant combinations and conjugates that are currently being investigated in human clinical trials.

Recent Advances in the Application of Barbituric Acid Derivatives in Multicomponent Reactions

Abstract:

Barbituric acid is a pyrimidine heterocyclic organic compound, which is pharmacologically active. It is important to build structures containing various medicinal activities. This compound attracts the scientific research community in organic synthesis. It can be used in the synthesis of polyheterocyclic, natural, medicinal compounds, and organic sensors. Herein, the utilization of barbituric or thiobarbituric acid in multicomponent reactions is reported from 2016-2021 in this manuscript.

Application of cyclohexane-1,3-diones for six-membered oxygen-containing heterocycles synthesis

Cyclohexan-1,3-dione derivatives are versatile scaffolds for the synthesis of a variety of value-added organic molecules including heterocycles and natural products. Six-membered oxygen heterocycles prepared from cyclohexan-1,3-diones are of much importance as they are intermediate for the synthesis of a number of natural products and several other valuable bioactive molecules which shows anti-viral, anti-bacterial, analgesic, antimalarial, anti-inflammatory, anti-allergic, anti-tumor and anti-cancer activities. These advantages have inspired us to write a detailed survey on the newly developed methods which are very essential in the construction of six-membered oxygen heterocycles. Further, the versatility in the chemistry of cyclohexan-1,3-dione and its derivatives is due to the presence of highly active methylene moiety and its active di-carbonyl groups. Recently, reactions of cyclohexane-1,3-dione and its derivatives with other substrates for instance aldehydes, malononitriles, NMSM, chalcones, isatin etc. have been established for the construction of a variety of six-membered oxygen heterocycles. The studies reported in this review article involved the synthesis of six-membered oxygen-containing heterocycles which includes 4H-chromen-5(6H)-one, 2H-xanthen-1(9H)-one, 2H-xanthen-1,8(5H,9H)-dione, 6H-chromen-2,5-dione derivatives and natural products having six-membered oxygen heterocycles from cyclohexane-1,3-dione and its derivatives as one of the substrate.

Multicomponent Reactions for Integrating Multiple Functional Groups into an Antioxidant

A large number of convincing evidences has revealed the correlation of the pathogeny of diseases with the oxidative damages of DNA, protein, biomembrane, and other biological species, while supplementation of antioxidants is demonstrated to be a promising way to avoid, at least, rectify the unbalance redox status in vivo. Although many endeavors have focused on synthesis of antioxidants, a main hurdle still hinders the wide usages of synthetic antioxidants because of low bioavailability and potential cytotoxicity. The search for antioxidants with multiple functional groups being recognized by different receptors becomes a much sought by researchers, and multicomponent reactions (MCRs) provide with powerful tools for the construction of multifunctional antioxidants. Presented herein is a personal account on the application of MCRs for the synthesis of multifunctional antioxidants, while radical-induced oxidation of DNA acts as the experimental system for evaluating antioxidative effect. Concretely, the Biginelli three-component reaction (3CR) affords such a dihydropyrimidine scaffold that the tautomerization between C=S and C-SH leads to antioxidative effect. The Povarov 3CR is able to integrate multiple antioxidative groups, i. e., ferrocenyl and -N(CH₃ )₂ , into a quinoline scaffold, while the Groebke 3CR provides with imidazo[1,2-a]pyridine skeleton for inhibiting DNA oxidation. Additionally, the Knoevenagel-related MCRs also become efficient strategies for achieving radical-scavengers. On the other hand, the Ugi 4CR and Passerini 3CR result in the dipeptide and α-acyloxycarboxamide, respectively, with the benefit for the integration of antioxidative features by aliphatic chains. Therefore, MCRs have emerged as efficient tools for integrating multiple antioxidative features into one molecule in order to meet with complicated requirements from various biological surroundings.

Synthesis of Biologically Active Molecules through Multicomponent Reactions

Focusing on the literature progress since 2002, the present review explores the highly significant role that multicomponent reactions (MCRs) have played as a very important tool for expedite synthesis of a vast number of organic molecules, but also, highlights the fact that many of such molecules are biologically active or at least have been submitted to any biological screen. The selected papers covered in this review must meet two mandatory requirements: (1) the reported products should be obtained via a multicomponent reaction; (2) the reported products should be biologically actives or at least tested for any biological property. Given the diversity of synthetic approaches utilized in MCRs, the highly diverse nature of the biological activities evaluated for the synthesized compounds, and considering their huge structural variability, much of the reported data are organized into concise schemes and tables to facilitate comparison, and to underscore the key points of this review.