Green synthesis and antibacterial, antifungal activities of 4H-pyran, tetrahydro-4H-chromenes and spiro2-oxindole derivatives by highly efficient Fe3O4@SiO2@NH2@Pd(OCOCH3)2 nanocatalyst

A double boronic acid affinity "sandwich" SERS biosensor based on magnetic boronic acid controllable-oriented imprinting for high-affinity biomimetic specific recognition and rapid detection of target glycoproteins

Transferrin (TRF), recognized as a glycoprotein clinical biomarker and therapeutic target, has its concentration applicable for disease diagnosis and treatment monitoring. Consequently, this study developed boronic acid affinity magnetic surface molecularly imprinted polymers (B-MMIPs) with pH-responsitivity as the "capture probe" for TRF, which have high affinity similar to antibodies, with a dissociation constant of (3.82 ± 0.24) × 10-8 M, showing 7 times of reusability. The self-copolymerized imprinted layer synthesized with dopamine (DA) and 3-Aminophenylboronic acid (APBA) as double monomers avoided nonspecific binding sites and produced excellent adsorption properties. Taking the gold nanostar (AuNS) with a branch tip "hot spot" structure as the core, the silver-coated AuNS functionalized with the biorecognition element 4-mercaptophenylboronic acid (MPBA) was employed as a surface-enhanced Raman scattering (SERS) nanotag (AuNS@Ag-MPBA) to label TRF, thereby constructing a double boronic acid affinity "sandwich" SERS biosensor (B-MMIPs-TRF-SERS nanotag) for the highly sensitive detection of TRF. The SERS biosensor exhibited a detection limit for TRF of 0.004 ng/mL, and its application to spiked serum samples confirmed its reliability and feasibility, demonstrating significant potential for clinical TRF detection. Moreover, the SERS biosensor designed in this study offers advantages in stability, detection speed (40 min), and cost efficiency. The portable Raman instrument for SERS detection fulfills the requirements for point-of-care testing.

Construction of a Dual-Functionalized Acid-Base Nanocatalyst via HEPES Buffer Functionalized on Fe3O4 as a Reusable Catalyst for Annulation Reactions

Herein, we present a highly efficient dual-functionalized acid-base nanocatalyst, denoted as Fe3O4@GLYMO-HEPES, featuring sulfuric acid and tertiary amines as its dual functional components. This catalyst is synthesized through the immobilization of 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) as the source of these functionalities onto magnetite (Fe3O4) using 3-glycidoxypropyltriethoxysilane (GLYMO) as a linker. Characterization studies confirm the integrity of the Fe3O4 core, with the GLYMO-HEPES coating exhibiting no phase changes. Furthermore, Fe3O4@GLYMO-HEPES nanoparticles demonstrate a uniform size distribution without aggregation. Notably, the catalyst exhibits remarkable stability up to 200 °C and possesses a saturation magnetization value of 31.5 emu/g, facilitating easy recovery via magnetic separation. These findings underscore the potential of Fe3O4@GLYMO-HEPES as a versatile and recyclable nanocatalyst for various applications. Its catalytic ability was evaluated in the synthesis of various pyrano[2,3-c]pyrazoles and 2-amino-3-cyano-4H-chromenes through a tandem Knorr-Knoevenagel-Michael-Thorpe-Ziegler-type heterocyclization mechanism, using different aldehydes. A wide range of fused heterocycles was synthesized having good to excellent yields. The process is cost-effective, safe, sustainable, and scalable, and the catalyst can be reused up to five times. The prepared catalyst was found to be highly stable and heterogeneous and showed good recyclability.

Design, Synthesis, Bioactive Evaluation, and Molecular Dynamics Simulation of Novel 4H-Pyrano[3,2-c]pyridine Analogues as Potential Sterol 14α-Demethylase (CYP51) Inhibitors

To discover potential sterol 14α-demethylase (CYP51) inhibitors, thirty-four unreported 4H-pyrano[3,2-c]pyridine derivatives were designed and synthesized. The assay results indicated that most compounds displayed significant fungicidal activity against Sclerotinia sclerotiorum, Colletotrichum lagenarium, Botrytis cinerea, Penicillium digitatum, and Fusarium oxysporum at 16 μg/mL. The half maximal effective concentration (EC50) values of compounds 7a, 7b, and 7f against B. cinerea were 0.326, 0.530, and 0.610, respectively. Namely, they had better antifungal activity than epoxiconazole (EC50 = 0.670 μg/mL). Meanwhile, their half maximal inhibitory concentration (IC50) values against CYP51 were 0.377, 0.611, and 0.748 μg/mL, respectively, representing that they also possessed better inhibitory activities than epoxiconazole (IC50 = 0.802 μg/mL). The fluorescent quenching tests of proteins showed that 7a and 7b had similar quenching patterns to epoxiconazole. The molecular dynamics simulations indicated that the binding free energy of 7a and epoxiconazole to CYP51 was -35.4 and -27.6 kcal/mol, respectively.

Synthesis and Characterization of a New Class of Chromene-Azo Sulfonamide Hybrids as Promising Anticancer Candidates with the Exploration of Their EGFR, hCAII, and MMP-2 Inhibitors Based on Molecular Docking Assays

In this study, novel selective antitumor compounds were synthesized based on their fundamental pharmacophoric prerequisites associated with EGFR inhibitors. A molecular hybridization approach was employed to design and prepare a range of 4H-chromene-3-carboxylates 7a-g, 8, and 11a-e derivatives, each incorporating a sulfonamide moiety. The structures of these hybrid molecules were verified using comprehensive analytical and spectroscopic techniques. During the assessment of the newly synthesized compounds for their anticancer properties against three tumor cell lines (HepG-2, MCF-7, and HCT-116), compounds 7f and 7g displayed remarkable antitumor activity against all tested cell lines, outperforming the reference drug Cisplatin in terms of efficacy. Consequently, these promising candidates were selected for further investigation of their anti-EGFR, hCAII, and MMP-2 potential, which exhibited remarkable effectiveness against EGFR and MMP2 when compared to Sorafenib. Additionally, docking investigations regarding the EGFR binding site were implemented for the targeted derivatives in order to attain better comprehension with respect to the pattern in which binding mechanics occur between the investigated molecules and the active site, which illustrated a higher binding efficacy in comparison with Sorafenib.

Synthesis and characterization of new 1,4-dihydropyran derivatives by novel Ta-MOF nanostructures as reusable nanocatalyst with antimicrobial activity

Novel Ta- MOF was synthesized under mild conditions by ultrasound irradiations. The sample was characterized by SEM, FTIR, XRD, XPS, TG and BET technique. The final structures showed high physicho-chemical properties including narrow particle size distribution, homogenous morphology, high thermal stability and remarkable surface area. Ta- MOF synthesized in this study was used as a catalyst in the synthesis of 1,4-dihydropyran derivatives. The results proved that it has a high catalyst capability. Its advantages include high recyclability, less reaction time with higher efficiency and synthesis of new1,4-dihydropyran derivatives. In the following, antimicrobial activity including antifungal and antibacterial activity of Ta- MOF nanoparticles based on Minimum Inhibitory Concentration, Minimum Fungicidal Concentration and Minimum Bactericidal Concentration were evaluated. The synthesized Ta- MOF, in addition to high catalytic properties, showed high antimicrobial activity with MIC value between 16 and −256 μg/ml, and can be introduced as an agent against bacteria and fungi.

Milk protein hydrolysates obtained with immobilized alcalase and neutrase on magnetite nanoparticles: Characterization and antigenicity study

Enzymatic hydrolysis is the most commonly used method to reduce the antigenicity of milk protein, but free protease is unstable and difficult to recycle after application. In this study, alcalase and neutrase were selected for immobilization on the modified magnetic Fe₃ O₄ nanoparticles. The reusability of the immobilized enzyme was 68.23% of the total starting activity after 5 recycling batches. The optimal hydrolysis conditions were an enzyme to substrate ratio of 6000 U/g and reaction at 50℃ and pH 8.5 for 3 h. Under these conditions, 22.76% hydrolysis of hydrolysate was achieved, and the antigenicity reduction rates of β-lactoglobulin and casein were 21.34% and 30.89%, respectively. In addition, 82.75% of the hydrolysate had a molecular weight less than 1 kDa, and free amino acids represented 13.65% of the sample. This result showed that the hydrolysis with immobilized enzyme was similar to that with free enzyme and the immobilized enzyme could be applied to produce hypoallergenic hydrolysate. PRACTICAL APPLICATION: Reduces milk protein allergenicity.

Magnetic UiO-66 functionalized with 4,4'-diamino-2,2'-stilbenedisulfonic as a highly recoverable acid catalyst for the synthesis of 4H-chromenes in green solvent

According to 4H-chromenes importance, we synthesized a novel magnetic UiO-66 functionalized with 4,4′-diamino-2,2′-stilbenedisulfonic as an efficient and reusable solid acid catalyst for synthesizing 4H-chromene skeletons via a one-pot three components reaction in a green solvent. The structure of the synthesized catalyst was confirmed by various techniques including FT-IR, XRD, BET, TGA, TEM, EDX, and SEM, and also the product yields were obtained in 83–96% of yields for all the reactions and under mild conditions. The reported procedure presents an environmentally friendly approach for synthesizing a significant number of 4H-chromene derivatives. Correspondingly, MOF-based catalyst makes it easy to separate from reaction media and reuse in the next runs.