Health Equity

Chetry A.B.

Bioorthogonal chemistry has emerged as a pivotal field in molecular science, offering transformative tools for applications in drug discovery, imaging, and molecular biology. This review provides a comprehensive analysis of recent advancements in bioorthogonal chemistry, emphasizing key innovations, practical applications, and future research directions. We explore state-of-the-art bioorthogonal reactions, including Staudinger ligation, strain-promoted azide-alkyne cycloaddition (SPAAC), and tetrazine ligation, detailing their mechanisms, advantages, and limitations. The review highlights significant innovations such as novel fluorogenic probes, improved catalysts, and enhanced reaction conditions that have expanded the utility and efficiency of these reactions. Practical applications are examined, showing how these advances have revolutionized fields like live-cell imaging, targeted drug delivery, and molecular labeling. Looking to the future, we discuss emerging trends and potential research avenues, including the integration of bioorthogonal chemistry with other advanced technologies and the development of new reaction methodologies. This review provides a detailed overview of the current state of bioorthogonal chemistry and outlines its future potential, serving as a valuable resource for researchers and practitioners in the field.

Bull O.S., Don-Lawson C.

A novel 1D polymer of 1,2-di(pyridin-4-yl)ethane (L1), connected via B-N dative-bonded adduct with an eight-membered cyclo-1,3,3,5,7,7-hexaphenyl-1,5-dibora-3,7-disiloxane [Ph6B2Si2O4]·L1 was synthesized and characterized. The new compound [Ph6B2Si2O4]·L1 was prepared by the reaction of cyclo-1,3,3,5,7,7-hexaphenyl-1,5-dibora-3,7-disiloxane and bis(pyridyl)ethane in a mixture of diethyl ether and petroleum ether solvents at reflux. The 1D polymer [Ph6B2Si2O4]·L1 was characterized by single-crystal X-ray diffraction, nuclear magnetic resonance, and FT-IR spectroscopy. The single crystal X-ray diffraction studies reveal that the aforementioned compound crystalized in the monoclinic crystal system with a centrosymmetric space group of P21/n (no. 14), a = 16.5378(4) Å, b = 12.6201(3) Å, c = 20.4904(5) Å, β = 96.689(2)°, V = 4247.43(18) Å3, Z = 4, T = 173.0 K, μ(MoKα) = 0.130 mm-1, Dcalc = 1.233 g/cm3, 14630 reflections measured (4.96° ≤ 2Θ ≤ 56.424°), 8424 unique (Rint = 0.0235, Rsigma = 0.0460) which were used in all calculations, the final R1 was 0.0455 (I > 2σ(I)) and wR2 was 0.1201 (all data). Furthermore, the compound exhibits various noncovalent interactions in the crystal packing, such as intermolecular and intramolecular, as well as hydrogen bonding. This study demonstrates the potential for making novel materials via the combination of cyclodiboradisiloxanes (Lewis acid) and nitrogen-containing ligands (Lewis bases).

Ndiolene A., Diop T., Boye M.S., Diasse-Sarr A.

The tin (IV) and cadmium (II) complexes were synthesized in mixture, the ligand 4,4'-(ethane-1,2-diylbis(azanylylidene))bis(pent-2-en-2-ol), and the halide metal (SnCl2 or CdI2). Complex synthesis involves partial hydrolysis of the ligand followed by condensation cyclization. The new tin complex obtained crystallizes in the monoclinic space group P21/n with a = 8.5468(5) Å, b = 17.9907(9) Å, c = 12.7227(7) Å, β = 94.220(5) °, V = 1950.98(18) Å3 and Z = 4. The asymmetric unit consists of an anion tetrachloro-(acetylacetonato)stannate(IV) and a heptacyclic cation. The geometry of the complex is octahedral with cis coordination of the two oxygens of the acetylacetone. The cadmium complex crystallizes in the orthorhombic space group Pbca with a = 14.7395(9) Å, b = 8.5914(5) Å, c = 23.2825(13) Å, V = 2948.3(3) Å3, Z = 8. The geometry around cadmium is a deformed tetrahedron. The heptacyclic cation and the anionic complex are interconnected through hydrogen bonding interactions, specifically N–H···Cl or N–H···I, forming a network.

Abosadiya H.M.

In the present work, a new carbonoyl thiourea derivative, N-(3-chloropropionyl)-N'-(4-methoxyphenyl)thiourea, was synthesized by the reaction of 3-chloropropionyl isothiocyanate with 4-methoxyaniline in acetone solution. The newly synthesized compound was characterized by FT-IR, 1H NMR, and 13C NMR spectroscopic techniques. X-ray crystallographic studies indicate that the compound crystallized in the triclinic crystal system with space group P-1 and unit cell dimension are a = 10.2262(6) Å, b = 11.5007(7) Å, c = 12.6116(8) Å, α = 72.253(2)°, β = 66.348(2)°, γ = 88.099(2)°, Z = 4 and V = 1287.22 (14) Å3. Strong intramolecular O-H···N hydrogen bonds are present that form a six-member pseudo-ring S(6). In the crystal structure, the molecules are linked by N-H···O, N-H···S, and C-H···O intermolecular hydrogen bonding interactions formed infinite one-dimensional chains with an R22(8) and R22(12) rings motif of molecules. The antioxidant test using the DPPH method showed that the compound exhibits a good antioxidant activity of about 80%.

Sow I.S., Vandeput M., Gelbcke M., Dufrasne F.

N-Hydroxydodecanamide (HA12) and its trihydroxamato-iron(III) complex (HA12Fe3) have been synthesized and characterized by various methods including structural determination by single crystal X-ray diffraction and cyclic voltammetry (CV). In order to complete our previous CV study on HA12 and its complexes, our aim was to investigate the variation in redox potential upon changes in concentration and pH. The redox couples previously observed with HA12 and HA12Fe3 at 100 µM shifts towards less positive values when the concentration or pH of the solution increases. These results indicate that oxidation is easier when concentrations are higher and in basic media. The slopes of -0.06 V/pH (in agreement with the theoretical data) and -0.077 V/pH (slightly higher than the theoretical slope) were observed for HA12 and HA12Fe3, respectively. This observation would explain the slower oxidation of HA12Fe3 than HA12.

Arslan H.

Graphical Contents

Sow I.S.

In previously published works, the antibacterial, antifungal, antimycobacterial and anticancer activities of hydroxamic acids (HA) and their complexes were reported. Our recently published work shows that aliphatic HA with a number of carbon atoms equal to 12 (C12) and its Fe(II), Fe(III), Ni(II), Cu(II) and Zn(II) complexes are significantly active against bacteria (Staphylococcus aureus, Escherichia coli), fungal (Candida albicans) and mycobacteria (Mycobacterium smegmatis). Furthermore, the inhibitory activities against biofilms of Mycobacterium tuberculosis, Mycobacterium bovis BCG, Mycobacterium marinum and Pseudomonas aeruginosa were observed with a large number of HA and their complexes. Suberoylanilide HA and resminostat were approved to treat cutaneous T cell lymphoma and in clinical trials to treat advanced hepatocellular carcinoma, respectively. In view of the interesting biological properties of this family of chemical compounds, the synthesis of HA has been reported in numerous research articles in recent years but this is the second review article dedicated to their synthetic methods and the first review for their complexes. The aim of this review is to highlight optimal and rational methods for the synthesis of HA and their complexes. HA are obtained in near-quantitative yields from carboxylic acid, ethyl chloroformate, N-methylmorpholine and hydroxylamine. As for their complexes, the synthesis methods described are fairly similar and would all appear to be optimal. The main criteria are the number of equivalents of HA, the type of metal salt or solvent used and the reaction conditions.

Khan S., Liza U.A., Banik D., Aman M.A., Happy K., Arjaya A.C., Hossain M.M.

Flavones have biological properties because of the existence of oxoheterocyclic ring moieties, and day by day create research interest areas because of their important biological activity. Iodine-substituted flavones were synthesized from the corresponding chalcones through an exhaustive iodination reaction. Generally, it is seen that halogenated flavones show better biological activity. Moreover, the introduction of iodine in the ring moiety facilitates the incorporation of highly active side chains, such as prenyl and geranyl groups through the formation of C-C bonds by numerous coupling reactions such as Sonogashira coupling. To achieve such target molecules, a planned chemical synthesis was conducted. For comparison, microwave irradiation (MWI) and conventional heating (CH) methods were used to synthesize a series of iodine-substituted flavone compounds with different substitutes (4a-d) from their corresponding chalcones (3a-d). Unfortunately, 3e chalcone (1-hydroxynapthalene substituted flavone) did not convert to 4e flavones. In the microwave method, a notable decrease in time required in the reaction and an increase in % yield of the reaction were remarked. Characterization and conformation of all synthesized compounds were done using ultraviolet, infrared, and nuclear magnetic resonance spectroscopy and elemental analysis.

Glitho H.A., Osseni S.A., Bonou S.S., Plaisier J., Gigli L., Sagbo E., Chouti W.K.

In order to valorize locally available natural resources, the silica sand in the commune of Sèmè-Podji in Republic of Benin was characterized. The results obtained by particle size, chemical analysis, X-ray diffraction (XRD), and FT-IR analysis confirmed that these sands contain a high percentage of silicon dioxide, with a value approximately equal to 90 wt.%. Low Fe2O3 and Al2O3 content (<1 wt.%) and minor oxides such as K2O, Na2O, TiO2, and P2O5 (<0.6%) were also present. The size distributions of the particles show that the largest portion of the sand is found between 63 and 125 μm. This portion represents the one that contains the most silica. From this sand, silica particles were synthesized by the sol-gel method. The results obtained by X-ray diffraction (XRD), FT-IR analysis, and scanning electron microscopy (SEM) reveal the formation of pure amorphous silica.

Suman A.K., Anu A., Singh B.

Heterocyclic scaffolds have attracted great attention of organic chemists and medicinal chemists, also because of their wide range of synthetic applicability and broad spectrum of biological profile. Therefore, in the present research work, a series of tetrazole containing 1,5-benzothiazepines have been synthesized for evaluation of their biological activities to determine the potential therapeutic profile of these compounds across various medicinal domains. Of the synthesized compounds, five compounds (6f, 8e, 8f, 8g, and 8h) have been screened for anticancer, antitubercular, antibacterial, and antifungal activities. After evaluation of these biological activities, it was found that these compounds possess very limited anticancer activity, moderate antibacterial and antifungal activity, and very strong antitubercular activity, which indicate their great pharmacological applications as subjects for future investigations of novel therapeutic agents for the treatment of tuberculosis.

Bull O.S., Don-Lawson C., Nweke-Maraizu U.

Simple adducts of cyclo-diboradisiloxanes (Lewis acid) and amines (Lewis base) have been reported in the literature. However, the method for the synthesis of an 8-membered cyclo-diboratetrasiloxane, as well as its adducts, was modified in this report to save cost and achieve new results. In the literature, the synthesis of cyclo-1,3,3,5,7,7-hexaphenyl-1,5-dibora-3,7-disiloxane (Ph6B2Si2O4) (3) has been reported using diphenylsilanediol and phenylboronic acid and a Dean-Stark apparatus for the removal of water. However, in this study, molecular sieves were used for the facile removal of water, and the crude product recrystallized from diethyl ether and petroleum ether (3:1 ratio) to give compound 3. Compound 3 was reacted with 4,4’-bipyridine in a mixture of diethyl ether and petroleum ether solvents at reflux to give a 1D polymer [Ph6B2Si2O4]·L1 (4). Furthermore, compound 4 was characterized with various characterization methods such as single-crystal XRD, nuclear magnetic resonance, and FT-IR spectroscopy. The single crystal X-ray diffraction studies shows that the title compound crystalizes in the triclinic crystal system in the centrosymmetric space group P-1, a = 10.9372(4) Å, b = 18.4221(6) Å, c = 19.4697(6) Å, α = 70.533(3)°, β = 86.476(3)°, γ = 88.517(3)°, V = 3691.6(2) Å3, Z = 2, T = 173.0 K, μ(MoKα) = 0.122 mm-1, Dcalc = 1.204 g/cm3, 21463 reflections measured (5.196° ≤ 2Θ ≤ 56.45°), 14525 unique (Rint = 0.0185, Rsigma = 0.0483) which were used in all calculations, the final R1 was 0.0721 (I > 2σ(I)) and wR2 was 0.2143 (all data)  with the 8-membered cyclo-1,3,3,5,7,7-hexaphenyl-1,5-dibora-3,7-disiloxane (Ph6B2Si2O4) (3) configuration.

Jagadeesan N., Kumar P., Gowda N.P., Karur K., Nanjappa M.C., Kumari P., Kumar H.T.

The novel SARS-CoV-2 (COVID-19) has caused widespread human turmoil by posing challenges concerning infection prevention, disease diagnosis, and treatment. Several approved vaccines including Sinovac (CoronaVac), COVISHIELD™ (Oxford/AstraZeneca formulation), Janssen (Johnson & Johnson), Sputnik V (Gamaleya), Covaxin (Bharat Biotech), Pfizer (BNT162b2), and others are being used to combat COVID-19. It is crucial to evaluate the kinetics of SARS-CoV-2 antibodies to predict the possibility of reinfection and the longevity of vaccination protection. There is a lack of data on longitudinal humoral antibody dynamics following two and three doses of the SARS-CoV-2 vaccination ChAdOx1-nCOV (COVISHIELDTM) in Indians. Thus, concerns about the efficacy of current vaccines have been raised by a sharp rise in coronavirus disease 2019 (Covid-19) cases caused by sub-variants of SARS-CoV-2 (Severe acute respiratory syndrome corona virus 2) in communities that have received massive vaccinations. The relative immunogenicity and safety of various COVID-19 immunizations administered as a third (booster) dose are not well known. We examined the reactogenicity and immunogenicity of the COVID-19 vaccine as a third dose after two doses of COVISHIELDTM to produce data to optimize the selection of booster vaccinations. After three doses of the COVID-19 vaccine, we evaluated the sera of COVISHIELDTM vaccine recipients for their ability to neutralize the virus. Primary immunization with two doses of COVISHIELDTM vaccine recipients provided significant protection against symptomatic disease caused by the SARS-CoV-2 variants. A COVISHIELDTM vaccine booster vaccine recipient substantially increased protection. The immunization findings showed a significant difference (p ≥ 0.001) between the COVID-19 naive vaccine (n = 438) and the sera of COVID-19-positive recovered subjects (n = 371) who received three doses of COVISHIELDTM. Our findings reveal that anti-RBD antibodies persist over time, which may reduce the probability of reinfection. A three-dose vaccination (n = 53) increases defense against variations by noticeably increasing cross-neutralizing antibody titers. Particularly against variants with antibody escape mutations.

Baviskar P.D., Kale A.D., Mahire V.N., Gosavi S.D., Dalal D.S., Mahulikar P.P.

The coumarin moiety plays an important role in the large number of natural products possessing different kinds of biological diversity. Coumarin carboxylic acids show a wide range of biological activities in the pharmaceutical and agricultural fields. Knoevenagel condensation is one of the important reaction pathways for synthesizing coumarin derivatives, and many methodologies have been developed to synthesize this class of compounds. A more environmentally friendly method of synthesizing 3-carboxy coumarins has been successfully carried out using 50% aqueous NaPTS hydrotropes at room temperature, along with various substituted 2-hydroxy benzaldehydes and Meldrum’s acid. This process involves Knoevenagel condensation followed by intramolecular cyclization, providing better product yields (78-95%).

Arslan H.

Graphical Contents

Shotonwa I.O., Oduwole A.P., Agosu O.M., Yusuf A.F., Eze S.O.

This review focuses on the crystal and molecular structures of single and mixed dithiocarbamate ligands of cobalt, rhodium, and iridium in the +3 oxidation state. The complexities of their chelating and bridging modes come into play through modification of the substituents on the carbamate nitrogen atoms of the ligands and additional coordination of secondary phosphino-containing ligands, culminating in various applications such as biological, analytical, medicine, and catalysis. Other considerations include the geometrical coordination environments around the metal centres and their comparison with isostructural congeners. The distortions around the metal centres and their subsequent effects on the symmetries of bonds in the primary and secondary coordination spheres are discussed. The trans-effects of secondary P-ligands and their effects on geometrical alignment and structural stability have become valuable yardsticks in analyzing structural modifications and stabilities.