Search

Abstract: Melia azedarach L., a species of the mahogany family (Meliaceae), has long been used as a folk medicine for various diseases. Recent studies on this plant revealed that this plant contains many interesting bioactivities such as antioxidant, antimicrobial, antiviral, antifeedant, antidiabetic, antifungal, and cytotoxic activities. A diverse range of organic compounds has been isolated from this species, such as triterpenoids, limonoids, degraded limonoids, steroids, lignans, flavonoids, and phenolics. This review article will give a comprehensive overview of the chemical constituents and biological activity of Melia azedarach.

Background: An efficient and green strategy for the synthesis of 2-arylbenzoxazoles using [Bmim]PF6 ionic liquid as a catalyst has been investigated via the condensation of oaminophenol with aldehydes. The microwave-assisted synthesis features some advantages such as good yield of products, broad substrate scope, short reaction time, and absence of metal catalyst and solvent. Furthermore, the synthesis could be conveniently expanded to a gram scale. Methods: 2-arylbenzoxazoles were obtained from o-aminophenol with aldehydes using [Bmim]PF6 ionic liquid as a catalyst under microwave irradiation at 80ºC, 120 W. Results: Twenty-three 2-arylbenzoxazole derivatives were furnished in good to excellent yields under optimized conditions. The structures of these compounds were confirmed by analysis of NMR data. In addition, the method could be conveniently expanded to gram scale. Conclusion: An efficient and straightforward protocol for the synthesis of 2-arylbenzoxazoles catalyzed by [Bmim]PF6 ionic liquid has been demonstrated. The synthesis delivers several advantages such as short reaction time, broad substrate scope, scalability, solvent-free conditions, and high efficiency. The reaction mechanism and applications of this synthesis are currently ongoing in our lab and will be reported in due course.

Background: Thiazole-containing compounds are widely found in natural products as well as synthetic sources. Many thiazole-based compounds possess a broad spectrum of bioactivities, and some of them are well-known drugs in the markets. The use of thiazole derivatives in other fields such as organic materials, cosmetics, and organic synthesis has also been widely reported. Due to a wide range of applicability, the synthesis of thiazole-containing compounds has attracted extensive interest from chemists, and many studies in the synthesis of thiazole skeleton have been reported recently. Objective: This review article will discuss recent studies in the synthesis of thiazoles (from 2012). Besides the well-established Hantzsch thiazole synthesis, a large number of novel methods have been developed for the synthesis of thiazole derivatives. In most cases, reaction mechanisms have also been described. Conclusion: The synthesis of thiazole derivatives has drawn great attention from chemists, and many studies in the synthesis of these heterocycles have been reported recently. The classical method, the Hantzsch thiazole synthesis has received great research interest from chemists. Moreover, many new methods have been established to synthesize thiazole-derived compounds. Unquestionably, more and more approaches to access thiazole skeleton will appear in the literature. The application of well-established thiazole synthesis methods to the synthesis of drugs, organic materials, and natural products will almost certainly be studied.

Abstract: Limonoids are the most representative metabolites present in the order Rutales, which includes the families Rutaceae, Meliaceae and Cneoraceae. They are tetranortriterpenoids with a 4,4,8-trimethyl-17-furanylsteroidal skeleton, containing several oxygenated functions. The Meliaceae family consists of 50 genera with more than 1400 species distributed in tropical and subtropical regions worldwide. Plants of this family are found to be rich in limonoids. Limonoids from Meliaceae family exhibit a diverse range of bioactivities cytotoxic, antioxidant, anti-inflammatory, antimicrobial, antimalarial, and antifeedant, activities and some of them have been commercially used for different purposes. Numerous studies on limonoids from Meliaceae family and their bioactivities have been reported recently. This review covers the isolation and structure determination of limonoids reported during 2012–2022. 1172 novel limonoids in 118 papers have been summarized. Furthermore, important biological activities of these limonoids have also been outlined. This review can provide useful information for medicinal and pesticidal chemistry and phytochemistry researchers who are interested in the chemistry and biology of limonoids.

Abstact: An efficient and green method for the Friedländer quinoline synthesis has been described. The synthesis was performed under microwave irradiation using ionic liquid [Bmim]HSO4 as a catalyst. A diverse range of quinoline derivatives was obtained in high yields from 2-aminoaryl aldehydes and ketones under solvent-free conditions.

Abstract: Lamellarin alkaloid is a large class of marine alkaloids with diverse bioactivities. These heterocycles have been isolated from diverse marine organisms, mainly ascidians and sponges. They possess a fused 14-phenyl-6H-[1]benzopyrano[40,30:4,5] pyrrolo[2,1- a]isoquinoline or non-fused 3,4-diarylpyrrole-2-carboxylate ring systems. Until now, more than 50 lamellarins have been isolated from marine organisms. Various lamellarins exhibit valuable bioactivities, such as cytotoxicity, topoisomerase I inhibition, protein kinases inhibition, multidrug resistance reversal, and anti-HIV-1 activity. Due to their valuable biological activity, the synthesis of lamerallins has received great attention of chemists and a vast number of synthetic methods have been developed. This article gives overview of studies on lamellarins isolation, their bioactivities, and synthetic approaches for their total synthesis.

An efficient method for the Sonogashira coupling reaction between aryl halides and terminal alkynes has been developed. The reaction was performed in ionic liquid 1-butyl-3- methylimidazolium tetrafluoroborate ([Bmim][BF4]) under microwave irradiation. High yields of products were obtained in a very short reaction time. Moreover, the medium and catalyst could be recovered and reused three times without considerable decrease in reaction yields.

Isoxazole derivatives are aromatic five-membered ring heterocyclic compounds with one oxygen atom and one nitrogen atom at adjacent positions. These compounds have a broad spectrum of applications in medicinal chemistry, such as antimicrobial, anticancer, antitumor, antitubercular, analgesic, anti-inflammatory, antidepressant, and anticonvulsant activities and some of them are well-known drugs for the treatment of various diseases in the market. The use of this class of compounds in agriculture as herbicides, insecticides have been widely reported. In organic materials, these compounds have been applied as semiconductors, single-walled nanotubes, liquid crystals, chiral ligands, scaffolds for peptidomimetics, dyes, and high-temperature lubricants. Isoxazole derivatives also play an important role in organic synthesis because they can be converted into several important synthetic units such as β-hydroxy ketones, γ -amino alcohols, α,β-unsaturated oximes, β -hydroxy nitriles, α-hydroxy-β-diketones, and β - dicarbonyl compounds. Due to such a wide range of applicability, the synthesis of isoxazole derivatives has attracted intensive research from chemists. This review will focus on considerable studies on the synthesis of isoxazoles which date back from 2012.

Supplemental material, sj-docx-1-npx-10.1177_1934578X231167229 for Phytochemical Analysis of the Essential Oils From the Rhizomes of Three Vietnamese Curcuma Species and Their Antimicrobial Activity by Hieu Tran-Trung, Xuan Duc Dau, Thi Chung Nguyen, Hien Nguyen-Thi-Thu, Hieu Nguyen-Ngoc, Thi Giang An Nguyen, Van Trung Hoang, Dang-Khoa Nguyen, Danh Duc Nguyen, Chen Tran Van and Le Duc Giang in Natural Product Communications

Supplemental material, sj-docx-1-npx-10.1177_1934578X231167229 for Phytochemical Analysis of the Essential Oils From the Rhizomes of Three Vietnamese Curcuma Species and Their Antimicrobial Activity by Hieu Tran-Trung, Xuan Duc Dau, Thi Chung Nguyen, Hien Nguyen-Thi-Thu, Hieu Nguyen-Ngoc, Thi Giang An Nguyen, Van Trung Hoang, Dang-Khoa Nguyen, Danh Duc Nguyen, Chen Tran Van and Le Duc Giang in Natural Product Communications

Procyanidin B1 is one of the natural dimeric flavonoids. It has established a great role in antioxidative activity. In the current study, we wish to provide crucial information on its antioxidative action by the DFT computational and docking approaches. From point of thermodynamic view, at the M062X/6-311G(d,p) level, the HAT (hydrogen atom transfer) and SPL-ET (sequential proton loss-electron transfer) are principal antioxidative routes of this compound in gas and methanol, respectively. OH groups of two phenyl rings of this molecule are likely to be the best antiradical sites. In the kinetics of the interactions with HOO

The antioxidative activity of natural product compound amurensin H (1) and its three synthetic compounds 5-(6-hydroxy-2-(4-hydroxyphenyl)benzofuran-3-yl)benzene-1,3-diol (2), (E)-2-(4-hydroxyphenyl)-4-(4-hydroxystyryl)benzofuran-6-ol (3), and (E)-5-(6-hydroxy-4-(4-hydroxystyryl)benzofuran-3-yl)benzene-1,3-diol (4) are extensively studied by DFT (density functional theory) method. At the theoretical B3LYP/6-311G(d,p) level, the HAT (hydrogen atom transfer) mechanism is assignable to compounds 1-4 in gas, but the SPL-ET (sequential proton loss-electron transfer) mechanism is the main way in water and methanol. The antioxidative actions of the studied compounds are mainly based on OH bond breakage, especially OH groups directly substituted at benzofuran nucleus. Amurensin H (1) is better than the remaining compounds due to 6-OH group. 1-6-OH induces the low bond BDE (bond dissociation enthalpy) and PA (proton affinity) values in thermal analysis. Importantly, the kinetic reaction of 1-6-OH + HOO• in methanol exerts the lowest ΔG# value of 5.6 kcal/mol and the highest K value of 1.983 x 1010 L/mol.s. At the B3LYP/6-311G(d,p)/LANL2DZ level, the successful formation of complex [Zn(compound 1)2(H2O)2] at 6-OH is confirmed by molecular orbital and UV-Vis spectroscopic analyses.

Benzo[b]thiophenes are aromatic heterocyclic compounds containing benzene and thiophene rings. This class of heterocycles is present in a large number of natural and non-natural compounds. Benzo[b]thiophene derivatives have a broad range of applications in medicinal chemistry such as antimicrobial, anticancer, antioxidant, anti-HIV and antiinflammatory activities. The use of benzo[b]thiophene derivatives in other fields has also been reported. Various benzo[b]thiophenes compounds have been employed as organic photoelectric materials, while several benzo[b]thiophenes have been used as organic semiconductors. Benzo[b]thiophenes have also been used as building blocks or intermediates for the synthesis of pharmaceutically important molecules. : Due to such a wide range of applicability, the synthesis of benzo[b]thiophene derivatives has attracted intensive research. Numerous mild and efficient approaches for the synthesis of benzo[b]thiophenes have been developed over the years. Different catalysts and substrates have been applied for benzo[b]thiophene synthesis. This review will focus on the studies in the construction of benzo[b]thiophene skeleton, which date back from 2012.

Objective: A new poly(ionic liquid)(PIL), poly(p-vinylbenzyltriphenylphosphine hexafluorophosphate) (P[VBTPP][PF6]), was synthesized by quaternization, anion exchange reaction, and free radical polymerization. Then a series of the PIL were synthesized at different conditions. Methods: The specific heat capacity, glass-transition temperature and melting temperature of the synthesized PILs were measured by differential scanning calorimeter. The thermal conductivities of the PILs were measured by the laser flash analysis method. Results: Results showed that, under optimized synthesis conditions, P[VBTPP][PF6] as the thermal insulator had a high glass-transition temperature of 210.1°C, high melting point of 421.6°C, and a low thermal conductivity of 0.0920 W m-1 K-1 at 40.0°C (it was 0.105 W m-1 K-1 even at 180.0°C). The foamed sample exhibited much low thermal conductivity λ=0.0340 W m-1 K-1 at room temperature, which was comparable to a commercial polyurethane thermal insulating material although the latter had a much lower density. Conclusion: In addition, mixing the P[VBTPP][PF6] sample into polypropylene could obviously increase the Oxygen Index, revealing its efficient flame resistance. Therefore, P[VBTPP][PF6] is a potential thermal insulating material.

Background: Fluid flow in microchannels is restricted to low Reynolds number regimes and hence inducing chaotic mixing in such devices is a major challenge. Over the years, the Immersed Boundary Method (IBM) has proved its ability in handling complex fluid-structure interaction problems. Objectives: Inspired by recent patents in microchannel mixing devices, we study passive mixing effects by performing two-dimensional numerical simulations of wavy wall in channel flow using IBM. Methods: The continuity and Navier-Stokes equations governing the flow are solved by fractional step based finite volume method on a staggered Cartesian grid system. Fluid variables are described by Eulerian coordinates and solid boundary by Lagrangian coordinates. A four-point Dirac delta function is used to couple both the coordinate variables. A momentum forcing term is added to the governing equation in order to impose the no-slip boundary condition between the wavy wall and fluid interface. Results: Parametric study is carried out to analyze the fluid flow characteristics by varying amplitude and wavelength of wavy wall configurations for different Reynolds number. Conclusion: Configurations of wavy wall microchannels having a higher amplitude and lower wavelengths show optimum results for mixing applications.

Pyrrole derivatives are nitrogen-containing heterocyclic compounds and widely distributed in a large number of natural and non-natural compounds. These compounds possess a broad spectrum of biological activities such as anti-infammatory, antiviral, antitumor, antifungal, and antibacterial activities. Besides their biological activity, pyrrole derivatives have also been applied in various areas such as dyes, conducting polymers, organic semiconductors. : Due to such a wide range of applicability, access to this class of compounds has attracted intensive research interest. Various established synthetic methods such as Paal-Knorr, Huisgen, and Hantzsch have been modified and improved. In addition, numerous novel methods for pyrrole synthesis have been discovered. This review will focus on considerable studies on the synthesis of pyrroles, which date back from 2014.

Furans are five-membered aromatic heterocycles containing one oxygen atom that are important building blocks in organic chemistry, but also as natural products found in various natural sources, mostly in plants, algae and microorganisms. In this review, we discussed recent advances in the synthesis of furan compounds. Some classical methods have been modified and improved, while other new methods have been developed. A vast variety of catalysts was used for these transformations. In many studies, furan synthesis reaction mechanisms were also investigated and proposed.

Background: Benzo[b]furan derivatives are oxygen-containing heterocyclic compounds consisting of fused benzene and furan rings and are present in a large number of natural and non-natural compounds. This class of compounds has a wide spectrum of biological activities, such as antiarrhythmic, anticancer, inflammatory, antioxidant, antimicrobial, and antiviral. Furthermore, benzo[b]furan derivatives have also been applied in various areas, such as organic electroluminescence device materials and organic dyes, photosensitizing material, organic synthesis as building blocks or intermediates. : Because of a broad range of applicability, the synthesis of benzo[b]furan derivative has drawn great attention of chemists and many studies on the synthesis of this class of compounds have been reported recently. This review will give an overview of benzo[b]furan preparation based on studies dating back to the year 2012. Objective: In this review, recent development in the synthesis of benzo[b]furans are discussed. There has been increasingly new methodologies for the construction of benzo[b]furans skeleton to improve efficiency or develop environmentally friendly procedures. In some studies, reaction mechanisms were also outlined. Conclusion: Many methods for the synthesis of benzo[b]furans have been reported recently. Most of them involve cyclization or cycloisomerization processes. Unquestionably, more imaginative strategies for the construction of benzo[b]furan skeleton will be established in the near future. Application of known methods to natural products or drug synthesis, on industrial scale for the synthesis of economically or medicinally important benzo[ b]furans will probably be paid attention to.

A simple, efficient and eco-friendly method for Baeyer-Villiger oxidation reaction has been developed. The reaction employed m-CPBA as the oxidant with Cu(OTf)2 catalyst and was carried out in CH2Cl2 at room temperature. Nine lactones and ester were obtained in excellent yield (85-94%). Furthermore, the catalyst could be reused twice without considerable loss in activity.

An efficient aza-Michael addition of secondary amines to some α,β-unsaturated esters hasbeen carried out using LiCLO4 as a catalyst. β-amino esters were obtained in high yields at roomtemperature without using solvent.

The synthesis of racemic (5R*,6R*)-6-(3-(tert-Butyldimethylsilyloxy)prop-1-ynyl)-5-hydroxypiperidin-2-one was accomplished in 10.3% overall yield over 7 steps. The key steps involved a Sonogashira coupling reaction to make an ene-yne ester and an azidolysis reaction of an epoxide ester to form a γ-lactone.