1.Highly Lewis Acidic Arylboronate Esters Capable of Colorimetric Turn-On Response.
Oehlke A1, Auer AA2, Schreiter K1, Friebe N1, Spange S3. Chemistry. 2015 Dec 1;21(49):17890-6. doi: 10.1002/chem.201500835. Epub 2015 Oct 22.
A series of boronate-π-acceptor compounds containing different types of π bridges (1,4-phenylen or thien-2,5-diyl or furan-2,5-diyl) that link the switchable boronate ester group with the efficient TCF acceptor group (TCF=2-dicyanomethylen-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran) has been synthesized. A TCF chromophore of this type undergoes transition to a donor-π-acceptor compound upon coordination of Lewis bases at the Lewis acidic boron center, which is accompanied by an enhanced intramolecular charge-transfer interaction. The Lewis acid character has been investigated by spectroscopic measurements (UV/Vis, NMR spectroscopies) as well as DFT and ab initio-based calculations. It is shown that the TCF acceptor group and thiophene or furan π-bridges directly bound to the boron atom cooperatively increase the Lewis acidity. UV/Vis titration experiments confirm fluoride binding constants in the range of up to 10(8) M(-1) in CH2 Cl2 . In addition to the strong boron fluoride binding motif, Lewis interactions also occur with weaker Lewis bases, such as pyridine or aliphatic alcohols.
2.Harvest Date Effects on Aroma Compounds in Aged Riesling Icewines.
Khairallah R1, Reynolds AG1, Bowen AJ1. J Sci Food Agric. 2016 Feb 1. doi: 10.1002/jsfa.7650. [Epub ahead of print]
BACKGROUND: Riesling icewine is an important product of the Ontario wine industry. The objective of this study was to characterize concentrations in aroma compounds in aged icewines associated with three harvest dates (H1, H2, H3) using stir bar sorptive extraction-gas chromatography-mass spectrometry and to make inferences, where appropriate, with respect to their roles in potential wine quality.
3.Ferulone A and ferulone B: two new coumarin esters from Ferula orientalis L. roots.
Razavi SM1, Nahar L2, Talischi H1, Sarker SD2. Nat Prod Res. 2016 Mar 18:1-7. [Epub ahead of print]
Ferula orientalis (Apiaceae) is a well-known perennial herb growing wild in Iran used in traditional medicine. To perform phytochemical studies, dried ground roots of F. orientalis were sequentially Soxhlet-extracted using n-hexane, dichloromethane and methanol. A combination of vacuum liquid chromatography and preparative thin-layer chromatographic analyses were performed to isolate coumarin esters. The structures of the isolated compounds were elucidated by spectroscopic means, and in vitro free-radical-scavenging property was determined by the DPPH assay. Two new coumarin esters, 7-O-(4,8,12,16-tetrahydroxy-4,8,12,16-tetramethyl-heptadecanoyl)-coumarinand 7-O-(4-hydroxy-4,8,12-trimethyl-trideca-7,11-dienoyl)-coumarin, named ferulone A and ferulone B, respectively, were isolated from the n-hexane extract of the roots of F. orientalis. Both compounds showed a low level of free-radical-scavenging property with the RC50 values of 0.252 and 0.
4.[Evaluation of Photo- and Cytotoxicity of Chlorin e6 Ester Derivatives and Their Liposomal Forms].
Zorina TE, Yankovsky IV, Kravchenko IE, Shman TV, Belevtsev MV, Zorin VP. Biofizika. 2015 Sep-Oct;60(5):922-30.
Photophysical characteristics and photosensitizing activity of the chlorin e6 dimethyl and trimethyl ester derivatives in various solution and their liposomal forms were studied. It was shown that in lipid vesicles chlorin e6 ester derivatives are predominantly in the monomeric state and possess optimal photophysical properties and high photochemical activity. The rate of redistribution of the chlorin e6 dimethyl ester from lipid vesicle to cells was higher as compared with that one of the chlorin e6 trimethyl ester. The increase of the serum concentration in the incubation medium has a different effect on processes of accumulation of the liposomal forms of the chlorin e6 dimethyl and trimethyl ester derivatives by the cells. Cell culture studies showed that application of liposomal forms of the chlorin e6 dimethyl and trimethyl ester derivatives significantly decreases their cytotoxicity but keeps high cytotoxic effect of photodynamic activity of the chlorin e6 ester derivatives.
