Anodic electrosynthesis of MIL-53(Al)-N(CH2PO3H2)2 as a mesoporous catalyst for synthesis of novel (N-methyl-pyrrol)-pyrazolo[3,4-b]pyridines via a cooperative vinylogous anomeric based oxidation

In this paper, the MIL-53(Al)-NH2 metal–organic frameworks (MOFs) was prepared based on the anodic electrosynthesis under green conditions. The anodic electrosynthesis as an environmentally friendly procedure was performed in the aqueous solution, room temperature, atmospheric pressure, and in the short reaction time (30 min). Also, the employed procedure was accomplished without the need for the ex-situ salt and base/probase additives as cation source and ligand activating agent at the constant current mode (10.0 mA cm−2). The electrosynthesized MOFs was functionalized with phosphorus acid tags as a novel mesoporous catalyst. This mesoporous catalyst was successfully employed for synthesis of new series (N-methyl-pyrrol)-pyrazolo[3,4-b]pyridines by one-pot condensation reaction of 3-methyl-1-phenyl-1H-pyrazol-5-amine, 3-(1-methyl-1H-pyrrol-2-yl)-3-oxopropanenitrile and various aromatic aldehydes (mono, bis and tripodal). This catalyst proceeded the organic synthetic reaction via a cooperative vinylogous anomeric based oxidation mechanism with a marginal decreasing its catalytic activity after recycling and reusability.

Antimycobacterial cycloartane derivatives from the roots of Trichilia welwistchii C. DC (Meliaceae)

Chemical investigation of the roots of Trichilia welwitschii yielded a cycloartane type terpenoid 28,29-bis-norcycloart-24-en-3β,4α,6α-triol (1), isolated as pure compound for the first time, three coumarins and three sterols. New cycloartane derivatives (1a) and (1b+1c) were obtained by hemi-synthetic reaction of compound 1. The structures of 1a–c were established by spectroscopic methods including 1D and 2D-NMR analysis, HR-EIMS, chemical transformations and by comparison of these data with those of related compounds. Evaluated for their antimycobacterial potential, compound 1 and 1b+1c were determined to show significant activities against Mycobacterium tuberculosis MIC values of 6.25 μg mL−1 while compound 1a displayed weak activity showing MIC > 100 μg mL−1. Compounds 2–4 displayed moderate activity with MIC values range from 12.5 to 50 μg mL−1.

SERRS Detection on Silver Nanoparticles Supported on Acid-Treated Melamine-Resin Microspheres

Melamine-resin microspheres were synthesized at a pH of 4.0 for 20 min and used as silver nanoparticle (AgNP) carriers for surface enhanced resonant Raman scattering (SERRS) detection. An acetic acid–treatment reaction was introduced into the fabrication of the final substrate. The SERRS performance of the substrate was effectively optimized by regulating excess formaldehyde and experimental parameters, such as acidity, number of treatments and reaction temperature in the acid-treatment reaction. Based on the SERRS detection, it was declared that a trace amount of oligomers with a certain degree of polymerization is necessary for the construction of SERRS hotspots. In addition, it is important to remove excess oligomers with reference to the synthetic reaction of the polymer materials, given the special role of oligomers and the wide application of polymer materials in SERRS detection.

Sustainable N-doped lignin-derived porous carbon for ion selectivity in capacitive deionization applications

As a green materials, we presented a high ion-selective N-doped lignin-derived porous carbon (NLC) treated with urea. The synthetic reaction occurred through self-assembly of a low toxic crosslinking agent (glyoxal),...

Methods and Strategies Used in Green Chemistry: A Review

Green chemistry plays an important role in the development of sustainable production systems which involves tremendous research efforts on the design of synthetic and analytical techniques through resource-efficient ways. The improvement in synthetic reaction performances encourages the modern society to minimize energy and reagent consumption and waste generation. Explosion of the chemicals are referred as extremely toxic substances and have been allied with major harmful health effects, though no cure has been established due to the lack of curative therapeutic approaches. In view of the facts, green chemistry strategies trigger a new hope in the synthesis of safer biologically active compounds to meet the demands of disease free environment. Here, we highlighted the development of various compounds and greener techniques such as ultrasoundassisted method, microwave-assisted method, green solvent reactions, solvent free reactions, biomolecules and nanoformulations as a new healthy approach.

N-Heterocyclic Carbene Triazolium Salts Containing Brominated Aromatic Motifs: Features and Synthetic Protocol

In this work, we provide a brief overview of the role of N-aryl substituents on triazolium N-heterocyclic carbene (NHC) catalysis. This synopsis provides context for the disclosed synthetic protocol for new chiral N-heterocyclic carbene (NHC) triazolium salts with brominated aromatic motifs. Incorporating brominated aryl rings into NHC structures is challenging, probably due to the substantial steric and electronic influence these substituents exert throughout the synthetic protocol. However, these exact characteristics make it an interesting N-aryl substituent, because the electronic and steric diversity it offers could find broad use in organometallic- and organo-catalysis. Following the synthetic reaction by NMR guided the extensive modification of a known protocol to enable the preparation of these challenging NHC pre-catalysts.

Synthetic Strategies and Computational Inhibition Activity Study for Triazinyl-Substituted Benzenesulfonamide Conjugates with Polar and Hydrophobic Amino Acids as Inhibitors of Carbonic Anhydrases

Various sulfonamide derivatives are intensively studied as anticancer agents owing to their inhibitory activity against human tumor-associated carbonic anhydrase isoforms. In this work, different synthetic procedures for the series of 1,3,5-triazinyl-aminobenzenesulfonamide conjugates with amino acids, possessing polar uncharged, negatively charged, and hydrophobic side chain, were studied and optimized with respect to the yield/purity of the synthesis/product as well as the time of synthetic reaction. These procedures were compared to each other via characteristic HPLC-ESI-DAD/QTOF/MS analytical product profiles, and their benefits as well as limitations were discussed. For new sulfonamide derivatives, incorporating s-triazine with a symmetric pair of polar and some less-polar proteinogenic amino acids, inhibition constants (KIs) against four human carboanhydrases (hCAs), namely cytosolic hCA I, II, transmembrane hCA IV, and the tumor-associated, membrane-bound hCA IX isoforms, were computationally predicted applying various methods of the advanced statistical analysis. Quantitative structure-activity relationship (QSAR) analysis indicated an impressive KI ratio (hCA II/hCA IX) 139.1 and hCA IX inhibition constant very similar to acetazolamide (KI = 29.6 nM) for the sulfonamide derivative disubstituted with Gln. The derivatives disubstituted with Ser, Thr, and Ala showed even lower KIs (8.7, 13.1, and 8.4 nM, respectively).

Folate-conjugated Helix lucorum hemocyanin – preparation, stability, and cytotoxicity

This is the first report on the modification of a hemocyanin from Helix lucorum (HlH), a large molluscan respiratory protein, with folic acid (FA). In a two-step synthetic reaction, we prepared samples of HlH conjugated with 20 and 50 FA residues denoted as FA-HlH-1 and FA-HlH-2, respectively. Comparison of the attenuated total reflectance–Fourier transform infrared spectra in the amide I band region showed a structural rearrangement in the HlH that is due to FA conjugation. The changes in the secondary structure were more noticeable for FA-HlH-2. The thermal stability of HlH was not significantly affected by the FA modification, which is consistent with the observed structural similarities with the native protein. Preliminary cytotoxicity assays showed that FA-HlH-1 and FA-HlH-2 stimulate fibroblast proliferation when applied in concentrations of 50 and 100 μg/well. A negligible reduction of fibroblast growth was observed only for FA-HlH-1 and FA-HlH-2, exposed to 200 μg/well for 48 h. We found that FA-HlH-2 exhibits a low to moderate cytotoxic effect on two breast cancer cell lines, which express folate receptors, a hormone-dependent (MCF-7) and a hormone-independent (MDA-MB-231). FA-HlH-2 protects nontransformed cells and affects only neoplastic cells, which could be an advantage, and the protein could have potential in combination with other chemotherapeutics.

Lipid Sponge Droplets as Programmable Synthetic Organelles

Living cells segregate molecules and reactions in various subcellular compartments known as organelles. Spatial organization is likely essential for expanding the biochemical functions of synthetic reaction systems, including artificial cells. Many studies have attempted to mimic organelle functions using lamellar membrane-bound vesicles. However, vesicles typically suffer from highly limited transport across the membranes and an inability to mimic the dense membrane networks typically found in organelles such as the endoplasmic reticulum. Here we describe programmable synthetic organelles based on highly stable nonlamellar sponge phase droplets that spontaneously assemble from a single-chain galactolipid and non-ionic detergents. Due to their nanoporous structure, lipid sponge droplets readily exchange materials with the surrounding environment. In addition, the sponge phase contains a dense network of lipid bilayers and nanometric aqueous channels, which allows different classes of molecules to partition based on their size, polarity, and specific binding motifs. The sequestration of biologically relevant macromolecules can be programmed by the addition of suitably functionalized amphiphiles to the droplets. We demonstrate that droplets can harbor functional soluble and transmembrane proteins, allowing for the co-localization and concentration of enzymes and substrates to enhance reaction rates. Droplets protect bound proteins from proteases, and these interactions can be engineered to be reversible and optically controlled. Our results show that lipid sponge droplets permit the facile integration of membrane-rich environments and self-assembling spatial organization with biochemical reaction systems.Significance statementOrganelles spatially and temporally orchestrate biochemical reactions in a cell to a degree of precision that is still unattainable in synthetic reaction systems. Additionally, organelles such as the endoplasmic reticulum (ER) contain highly interconnected and dense membrane networks that provide large reaction spaces for both transmembrane and soluble enzymes. We present lipid sponge droplets to emulate the functions of organelles such as the ER. We demonstrate that lipid sponge droplets can be programmed to internally concentrate specific proteins, host and accelerate biochemical transformations, and to rapidly and reversibly sequester and release proteins to control enzymatic reactions. The self-assembled and programmable nature of lipid sponge droplets will facilitate the integration of complex functions for bottom up synthetic biology.