Highly selective detection of Cu2+ based on a thiosemicarbazone triphenylacetylene fluorophore

A novel thiosemicarbazone fluorophore (3) was successfully synthesized in 3 steps via Sonogashira coupling and Knoevenagel condensation using baker's yeast (Saccharomyces cerevisiae) as a biocatalyst. Compound 3 contains triphenylacetylene, which acts as a fluorophore, and thiosemicarbazone, which acts as a copper probe. Compound 3 exhibited highly selective detection of Cu²⁺ ions based on photoinduced electron transfer (PET) in 10 mM HEPES buffer pH 7.4/propylene glycol (70% (v/v)). A linear relationship was observed for Cu²⁺ concentrations between 0.1 nM and 10 μM, and the detection limit of the method was 0.14 nM. Additionally, 3 was utilized to detect Cu²⁺ in wastewater with satisfactory results, which highlighted its potential for real sample applications.     

Mesoporous soft solid electrolyte-based quaternary ammonium salt

Journal of Solid State Electrochemistry - A novel mesoporous soft solid electrolyte was successfully prepared from tetrabutylammonium hexafluorophosphate, propylene carbonate, and...     

Effect of Heat Treatment Temperature on Surface Topography and Hydrophobicity of Polydimethylsiloxane/Titanium Oxide Hybrid Films

Hydrophobic thin films of polydimethylsiloxane (PDMS) - titamium (hydrous) oxide hybrid material were deposited on glass substrate by dip coating from the precursor containing hydroxyl-terminated PDMS and titanium tetraisopropoxide (TIP), as well as small amounts of water and ethyl acetoacetate. Film's hydrophobicity was evaluated by performing contact angle measurement, while surface topography was analyzed by using an atomic force microscope (AFM). Effects of heat treatment temperature and TIP:PDMS ratio on film's hydrophobicity are described.     

<Emphasis Type="Italic">seco</Emphasis>-Kaurane skeleton diterpenoids from <Emphasis Type="Italic">Croton oblongifolius</Emphasis>

A new seco-kaurane type diterpenoid, ent-3,4-seco-17-oxo-kaur-4(19),15(16)-dien-3-oic acid, and a known compound, ent-3,4-seco-kaur-4(19),16(17)-dien-3-oic acid, were isolated from the stem bark of Croton oblongifolius. The structures of these compounds were established on the basis of spectroscopic data.     

Evaluation of tyrosinase inhibitory activity in Salak (<Emphasis Type="Italic">Salacca zalacca</Emphasis>) extracts using the digital image-based colorimetric method

A simple toolbox was developed for the evaluation of tyrosinase inhibitory activity in Salak (Salacca zalacca) extracts by the colorimetric measurement based on a photograph taken by a digital camera or a smartphone camera. The reaction of 3,4-dihydroxyphenylalanine (l-DOPA) and tyrosinase was employed to form the dopaquinone dye, which decreases with the increase of the tyrosinase inhibitor. Under the optimum conditions, the Salak extracts were examined for the tyrosinase inhibitory activity. The captured picture of dopaquinone dye product was analyzed by reading blue color intensity using an Adobe Photoshop CS6 program. The tyrosinase inhibition of the extracts was calculated from the blue color intensity, and expressed as %inhibition and IC₅₀ values. The obtained results from the developed method correlated well with those obtained from the microplate reader instrument. The achievement of this research will be a guideline for creating any simple analytical instrument based on colorimetry. In addition, the information on tyrosinase inhibitory activity of the Salak extracts is useful for the application of this fruit to produce the supplement food and the cosmetic in the future.     

Synthesis of ent-ambrox® from (−)-nidorellol

Using ozonolysis of the acid-catalyzed cyclized products of (−)-nidorellol and air-autoxidation as the key steps, (+)-ambrox was obtained in 53% overall yield. In the course of our synthesis, we discovered that (−)-nidorellol provided (+)-ambrox instead of the expected product, (−)-ambrox. Thus the absolute configuration of (−)-nidorellol was proved to be trans-(5R^∗,7R^∗,8R^∗,9S^∗,10R^∗)-labda-12,14-diene-7α,8β-diol, which is opposite to that illustrated in a previous report.     

Intermolecular Stereospecific Substitution of Underivatized Enantioenriched Secondary Alcohols by Organocatalysis

The stereospecific substitution of non‐derivatized and non‐allylic enantioenriched alcohols with only water as a by‐product would enable the use of readily available alcohols as substrates for green and sustainable transformations. However, the poor leaving group ability of the OH group has hampered the development of such a process. Denton and co‐workers recently described the use of (2‐hydroxybenzyl)diphenylphosphine oxide as a catalyst of a redox‐neutral and zero‐waste‐generating Mitsunobu reaction. This innovative process constitutes the first intermolecular stereospecific substitution of non‐allylic alcohols, and might find industrial applications.     

Formal synthesis of schulzeines B and C

A formal synthesis of schulzeines B and C, marine natural products with inhibitory effect against α-glucosidase, has been achieved. The key reactions of the synthesis are N-acyliminium ion cyclization, Sharpless asymmetric dihydroxylation, olefin cross metathesis, and asymmetric allylboration.