Olayinka O. Ajani

Towards the conversion of carbohydrate biomass feedstocks to biofuels via hydroxylmethylfurfural

This review appraises the chemical conversion processes recently reported for the production of hydroxylmethylfurfural (HMF), a key biorefining intermediate, from carbohydrate biomass feedstocks. Catalytic sites or groups required for the efficient and selective conversion of hexose substrates to HMF are examined. The principle of concerted catalysis was used to rationalise the dehydration of fructose and glucose to HMF in non-aqueous media. A survey of reported reaction routes to diesel-range biofuel intermediates from HMF or furfural is presented and self-condensation reaction routes for linking two or more HMF and furfural units together toward obtaining kerosene and diesel-range biofuel intermediates are highlighted. The reaction routes include: benzoin condensation, condensation of furfuryl alcohols, hetero Diels–Alder reaction and ketonisation reaction. These reaction routes are yet to be exploited despite their potential for obtaining kerosene and diesel-range biofuel intermediates exclusively from furfural or hydroxylmethylfurfural.

“Microwave assisted synthesis and antimicrobial activity of 2-quinoxalinone-3-hydrazone derivatives”

A simple and efficient method has been developed for the synthesis of various 2-quinoxalinone-3-hydrazone derivatives using microwave irradiation technique. The series of 2-quinoxalinone-3-hydrazone derivatives synthesized, were structurally confirmed by analytical and spectral data and evaluated for their antimicrobial activities. The results showed that this skeletal framework exhibited marked potency as antimicrobial agents. The most active antibacterial agent was 3-{2-[1-(6-chloro-2-oxo-2H-chromen-3-yl)ethylidene]hydrazinyl}quinoxalin-2(1H)-one, 7 while 3-[2-(propan-2-ylidene)hydrazinyl]quinoxalin-2(1H)-one, 2 appeared to be the most active antifungal agent.

Present status of quinoxaline motifs: excellent pathfinders in therapeutic medicine.

Quinoxalines belong to a class of excellent heterocyclic scaffolds owing to their wide biological properties and diverse therapeutic applications in medicinal research. They are complementary in shapes and charges to numerous biomolecules they interact with, thereby resulting in increased binding affinity. The pharmacokinetic properties of drugs bearing quinoxaline cores have shown them to be relatively easy to administer either as intramuscular solutions, oral capsules or rectal suppositories. This work deals with recent advances in the synthesis and pharmacological diversities of quinoxaline motifs which might pave ways for novel drugs development.

Functionalized 1,4‐Benzothiazine: A Versatile Scaffold with Diverse Biological Properties

1,4‐Benzothiazines are known to represent a class of medicinally important heterocyclic compounds which are extensively used in drug design. They have wide biological properties which qualify them as excellent scaffolds in therapeutic and medicinal research. Thus, many derivatives of this compound have been synthesized as target structures in novel drug development. Hence, the motivation for this present review was the known widespread application of the 1,4‐benzothiazine scaffolds.

Functionalized Benzimidazole Scaffolds: Privileged Heterocycle for Drug Design in Therapeutic Medicine

Benzimidazole derivatives are crucial structural scaffolds found in diverse libraries of biologically active compounds which are therapeutically useful agents in drug discovery and medicinal research. They are structural isosteres of naturally occurring nucleotides, which allows them to interact with the biopolymers of living systems. Hence, there is a need to couple the latest information with the earlier documentations to understand the current status of the benzimidazole nucleus in medicinal chemistry research. This present work unveils the benzimidazole core as a multifunctional nucleus that serves as a resourceful tool of information for synthetic modifications of old existing candidates in order to tackle drug resistance bottlenecks in therapeutic medicine. This manuscript deals with the recent advances in the synthesis of benzimidazole derivatives, the widespread biological activities as well as pharmacokinetic reports. These present them as a toolbox for fighting infectious diseases and also make them excellent candidates for future drug design.

Facile Synthesis and Characterization of New 2,3-Disubstituted Benzimidazole Derivatives

Benzimidazoles are known to represent a class of medicinally i mportant compounds which are extensively used as antibacterial agents. Hence, a series of five 2

Room Temperature Synthesis and Antibacterial Activity of New Sulfonamides Containing N,N-Diethyl-Substituted Amido Moieties

Sulfonamide drugs which have brought about an antibiotic revolution in medicine are associated with a wide range of biological activities. We have synthesized a series of α-tolylsulfonamide, 1–11 and their substituted N,N-diethyl-2-(phenylmethylsulfonamido) alkanamide derivatives, 12–22 in improved and excellent yields in aqueous medium at room temperature through highly economical synthetic routes. The chemical structures of the synthesized compounds 1–22 were confirmed by analytical and spectral data such as IR, 1H- and 13C-NMR, and mass spectra. The in vitro antibacterial activity of these compounds along with standard clinical reference, streptomycin, was investigated on two key targeted organisms. It was observed that 1-(benzylsulfonyl)pyrrolidine-2-carboxylic acid, 2 emerged as the most active compound against Staphylococcus aureus at MIC value of 1.8 μg/mL while 4-(3-(diethylamino)-3-oxo-2-(phenylmethylsulfonamido) propyl)phenyl phenylmethanesulfonate, 22 was the most active sulfonamide scaffold on Escherichia coli at MIC value of 12.5 μg/mL.

Cu(II) and Fe(III) complexes of sulphadoxine mixed with pyramethamine: Synthesis, characterization, antimicrobial and toxicology study

Two new mixed ligands metal complexes of sulphadoxine and pyramethamine were prepared by using CuCl2.6H2O and FeCl3.6H2O. The complexes were characterized by elemental analysis, melting point determination, molar conductivity, metal content analysis (AAS), IR, magnetic susceptibility measurements and UV-Visible spectroscopy. Based on the analytical and spectroscopic data, the complexes were proposed to have the formulae [M1L1L2(Cl)2] and [M2L1L2(Cl)3] (where M1 = Cu(II), M2 = Fe(III)), L1 = sulphadoxine, L2 = pyramethamine). The spectroscopic data proposed L1 to be a monodentate ligand and coordinated through N atom of the NH2 group in both complexes. Also, L2 was proposed to be tridentate ligand and coordinated through N atom of the NH2 groups and through N atom of imine group. However, [M1L1L2(Cl)2] and [M2L1L2(Cl)3] were proposed to possess distorted octahedral geometry. Conductivity measurement values supported the non-electrolytic nature of the complexes. The complexes have been tested in vitro against a number of pathogenic bacteria [g(+) Escherichia coli, g(+) Proteus species, g(+) Pseudomonas aeruginosa and g(+) Salmonella typhi] by using disc diffusion method. Obtained results indicated that the metal complexes exhibited better antibacterial activities as compared to the ligands. Toxicology tests against some tissues of albino rat (Rattus novergicuss) revealed toxicity of the complexes in the kidney as compared to the parent drugs. [M1L1L2(Cl)2] was found to be toxic to the sera, livers and kidneys of the rats used, while [M 2L1L2(Cl)3] was found to be non-toxic to the sera, livers and kidneys of the rats as their alkaline phosphatase (ALP) values showed non-significant difference to the control values.

Modeling and Synthesis of Ag and Ag/Ni Allied Bimetallic Nanoparticles by Green Method: Optical and Biological Properties

In the quest for environmental remediation which involves eco-friendly synthetic routes, we herein report synthesis and modeling of silver nanoparticles (Ag NPs) and silver/nickel allied bimetallic nanoparticles (Ag/Ni NPs) using plant-extract reduction method. Secondary metabolites in the leaf extract of Canna indica acted as reducing agent. Electronic transitions resulted in emergence of surface plasmon resonance in the regions of 416 nm (Ag NPs) and 421 nm (Ag/Ni NPs) during optical measurements. Further characterizations were done using TEM and EDX. Antimicrobial activity of the nanoparticles against clinical isolates was highly significant as P < 0.05. These findings suggest application of Ag NPs as antibacterial agent against E. coli, S. pyogenes, and antifungal agent against C. albicans. Possible antibacterial drugs against S. pyogenes and E. coli can also be designed using Ag/Ni nanohybrid based on their strong inhibition activities. Similarly, the enhanced SPR in the nanoparticles is suggested for applications in optical materials, as good absorbers and scatters of visible light. Theoretical model clarified that the experiment observation on the relationship between metallic nanoparticles penetration through peptidoglycan layers and the activeness of microbial species depends on the nature of the nanoparticles and pore size of the layer.

Corrosion Inhibitive Effect of 2-(1-(2-Oxo-2H-Chromen-3-Yl) Ethylidene) Hydrazine Carboxamide on Zinc-Aluminum Alloy in 1.8M Hydrochloric Acid

Introduction: Ethiopian communities highly depend on local plants to safe and sound their survival and health. Local trees are subjugated and used intensively for medicinal uses. Objective: The aim of the present study was too carried out phytochemical analysis of organic extract of Hagenia abyssinica and to find out antihelmentic property of Hagenia abyssinica. Methods: Hagenia abyssinica female flower extracts was used for plant component analysis and for determination of antihelmentic activity. Earth worm (Pheretima posthuma) strains were used for experimental purpose. Disc diffusion method was used to assess the antibacterial effect of the extracts on micro-organisms. Results: The phytochemical screening indicated the presence of flavonoids, tannins, steroid, alkaloid, saponins in all extracts. Antibacterial and antihelmentic activity of Ethanolic, Methanolic, Hexane and Petroleum Ether extract of Hagenia abyssinica female flowers was highly active against Adult earthworm (Pheritima posthuma) and active against Staphyloccoccus aureus and showed less activity against Salmonella typhi. Conclusion: The present study finally demonstrates that Hagenia abyssinica is a good source of various phytochemical such as Saponins, Phlobathanins, Flavonoids, Anthraquinones, Phenols, Terpenoids, Alkaloids, Steroids, Glycosides, Tannins. The antibacterial activity Hagenia abyssinica was clearly shown by the present study against bacteria. All these preliminary reports affirm an in depth analysis of the usefulness of Hagenia abyssinica as miracle drug against various ailments.