We present an important update of our research concerning the synthesis and application in asymmetric transfer hydrogenation (ATH) of a 3rd-generation ansa-ruthenium(II) complexes featuring N,C-alkylene-tethered N,N-dialkylsulfamoyl-DPEN/6-arene ligands. Employing a S/C = 1000, enantioselectivities up to )99.9% coupled with 100% conversion were attained in HCO2H/Et3N mixture for a variety of (het)aryl ketones and benzo-fused cyclic ketones. In particular, excellent enantioselectivities were obtained for 1-tetralone, 4-chromanone, thiochroman-4-one, and 1,3-diphenyl-1,3-propanedione.
We presented a synthesis of a new series of C1-symmetrical mono-P-stereogenic diphosphines possessing a rigid o-phenylene backbone, and their results in Rh(I)-catalyzed hydrogenation of olefins. This data-driven investigation, taking into account also the results of other diphosphine studies, demonstrated in a practical manner the impact on catalysis of modifying skeletal features typical to homologous C2-symmetrical P-stereogenic diphosphines with a flexible ethylene-backbone. In addition, this study filled some critical literature gaps (and correct some data) related to Rh(I)-catalyzed hydrogenation using P-stereogenic diphosphines.
This study compared two hop cultivars cv. ‘Aurora’ and cv. ‘Hallertauer Magnum’ from four different hop-growing countries. The leaves and cones were collected and their total phenolics and the antioxidative and antimicrobial activities of their ethanol extracts were determined. Total phenolics ranged from 0.099 to 0.542 mg CAE/mL for the leaf extract and from 0.738 to 1.734 mg CAE/mL for the cones. The leaves had much lower DPPH radical scavenging activity. The best reducer was the extract from the Aurora leaves collected in the Czech Republic. Antimicrobial activity against gram positive Staphylococcus aureus was extraordinary for all hop cones extracts, while moderate antimicrobial activity against gram negative Escherichia coli O157:H7 was observed for hop cones and leaves extracts.
Satureja montana L. and S. subspicata Vis. (Lamiaceae) are used for centuries in traditional medicine in the treatment of the respiratory system and lymphatic nodule inflammation. In this paper the content of phenolic compounds, quantity of total phenols and total flavonoids, antioxidant and antimicrobial activities were investigated in fourteen populations (seven per species) of S. montana and S. subspicata. Eight phenolic compounds (rutin, quercetin, caffeic, p-coumaric, ellagic, protocatehuic, rosmarinic, and syringic acid) were identified and quantified in methanolic and ethanolic extracts. Results showed that both species are a source of polyphenolics and other antioxidants with radical-scavenging. The extracts prepared from both species showed broad spectrum of antimicrobial activity on in vitro tested microbial species (Staphylococcus aureus, Escherichia coli, Candida albicans, C. dubliniensis, C. parapsilosis, C. krusei, C. glabrata, and Microsporum gypseum).
G-rich segments are highly populated in biologicaly crucial DNA regions. A large, still growing repertoire of possible G-quadruplex topologies differing in the orientation of their DNA strands and the types of connecting loops that a G-rich oligonucleotide can adopt has made the prediction of G-quadruplex topology very challenging. We have initiated a study to explore sequence directionality as a factor that is inherently connected with the folding of G-rich oligonucleotides. Intuitively we could expect that reversing the sequence direction from a 5’-3’ to 3’-5’ would cause dramatic changes in topology and/or the number of formed structures. The melting temperatures of G-quadruplexes adopted by oligonucleotides with sequences in the 5’-3’ direction are higher than those of their 3’-5’ counterparts. NMR study has demonstrated that a mere sequence reversal of the G-rich DNA segment exerts a substantial impact on the polymorphic nature of the resulting G-quadruplexes and thus their potential physiological roles.