Acid-Catalyzed Reactions of 2,3-Epoxy Derivatives of Citral with Alcohols

Acid-catalyzed reactions of 2,3-epoxy derivatives of citral (which is a widely spread naturally occurring unsaturated aldehyde) with alcohols were studied under conditions of heterogeneous catalysis and in fluorosulfonic acid. A number of new products were obtained, and possible mechanisms of their formation were proposed.     

Kinetics and mechanisms of the UV-radiation-assisted formation of gold nanoparticles in HAuCl<Subscript>4</Subscript>-doped chitosan solutions

Using methods of optical spectroscopy and small-angle X-ray scattering, the kinetics of the UV radiation-induced formation of gold nanoparticles in HAuCl₄-doped water–acid solutions of chitosan has been studied from the very beginning of the reaction. It has been shown that, during synthesis, as the mean size of nanoparticles grows from 2.9 to 6.3 nm, the maximum of the plasmon resonance shifts toward shorter waves (535–523 nm), whereas for a fully formed ensemble of nanoparticles, the reverse trend is observed. It has been found experimentally that the particle size distribution curve changes during synthesis. Based on the inverse problem analysis, conclusions have been drawn regarding the dominant mechanisms behind nanoparticle growth.     

Complexes of Zn(II) and Сu(II) with the Amino Derivatives of Deoxycholic Acid: Syntheses,Structures, and Properties

Russian Journal of Coordination Chemistry - Complexes [Zn(L)Cl2] (I), Cu(L)Cl2 ? H2O (II), Zn(L1)Cl2 ? 0.5H2O (III), and Cu(L1)Cl2 ? 0.5H2O (IV) (where L and L1 are the...     

Transformations of diepoxy derivatives of limonene in homogeneous acidic media

Transformations of diepoxy derivatives of limonene under conditions of homogeneous acid catalysis were studied, and their results were compared with those obtained over heterogeneous catalysts. A number of previously unknown compounds were isolated. The most possible transformation pathways were analyzed by computer simulation using molecular-mechanics and quantum-chemical methods.     

Tributylborane in the synthesis of graft copolymers of collagen and polymethyl methacrylate

Russian Chemical Bulletin - Graft copolymers of collagen and polymethyl methacrylate were synthesized in a suspension of an acetic acid dispersion of fish collagen and methyl methacrylate in the...     

Transformations of Isocaryophyllene Diepoxide under Conditions of Homogeneous and Heterogeneous Acid Catalysis

Transformations of isocaryophyllene diepoxide (an isomer of widely spread natural sesquiterpene) were studied in various acidic media under conditions of homogeneous and heterogeneous catalysis. A number of previously unknown compounds were thus obtained. The experimental data were compared with the results of molecular-mechanics and quantum-chemical simulation of the most probable transformation paths.     

New chiral ligands from myrtenal and caryophyllene for asymmetric oxydation of sulfides catalyzed by metal complexes

From myrtenal and caryophyllene, widespread terpene compounds, three new chiral Schiff bases were prepared suitable for ligands in vanadium ions catalyzed sulfides oxidation to chiral sulfoxides.     

High-contrast mapping of basal cell carcinomas

Because of low optical contrast in the visible spectral range, accurate detection of basal cell carcinomas (BCC) remains a challenging problem. In this letter, we experimentally demonstrate that reflectance confocal imaging in the vicinity of 1300 nm can be used for the detection of BCC without exogenous contrast agents. We present high-contrast reflectance confocal images of thick fresh skin tissues with clearly delineated cancer and discuss possible reasons for causing decreased scattering of BCC. Comparison with histopathology confirms that tumors scatter less and exhibit lower pixel values in the images, as compared to benign skin structures. The results demonstrate the feasibility of real-time noninvasive detection of BCC using intrinsic differences in scattering between tumors and normal skin.     

Cyano Enone-Bearing Triterpenoid Soloxolone Methyl Inhibits Epithelial-Mesenchymal Transition of Human Lung Adenocarcinoma Cells In Vitro and Metastasis of Murine Melanoma In Vivo

Introduction of α-cyano α,β-unsaturated carbonyl moiety into natural cyclic compounds markedly improves their bioactivities, including inhibitory potential against tumor growth and metastasis. Previously, we showed that cyano enone-bearing derivatives of 18βH-glycyrrhetinic (GA) and deoxycholic acids displayed marked cytotoxicity in different tumor cell lines. Moreover, GA derivative soloxolone methyl (SM) was found to induce ER stress and apoptosis in tumor cells in vitro and inhibit growth of carcinoma Krebs-2 in vivo. In this work, we studied the effects of these compounds used in non-toxic dosage on the processes associated with metastatic potential of tumor cells. Performed screening revealed SM as a hit compound, which inhibits motility of murine melanoma B16 and human lung adenocarcinoma A549 cells and significantly suppresses colony formation of A549 cells. Further study showed that SM effectively blocked transforming growth factor β (TGF-β)-induced epithelial-mesenchymal transition (EMT) of A549 cells: namely, inhibited TGF-β-stimulated motility and invasion of tumor cells as well as loss of their epithelial characteristics, such as, an acquisition of spindle-like phenotype, up- and down-regulation of mesenchymal (vimentin, fibronectin) and epithelial (E-cadherin, zona occludens-1 (ZO-1)) markers, respectively. Network pharmacology analysis with subsequent verification by molecular modeling revealed that matrix metalloproteinases MMP-2/-9 and c-Jun N-terminal protein kinase 1 (JNK1) can be considered as hypothetical primary targets of SM, mediating its marked anti-EMT activity. The inhibitory effect of SM on EMT revealed in vitro was further confirmed in a metastatic model of murine B16 melanoma: SM was found to effectively block metastatic dissemination of melanoma B16 cells in vivo, increase expression of E-cadherin and suppress expression of MMP-9 in lung metastatic foci. Altogether, our data provided valuable information for a better understanding of the antitumor activity of cyano enone-bearing semisynthetic compounds and revealed SM as a promising anti-metastatic drug candidate.