Profiling the Major Aroma-Active Compounds of Microwave-Dried Jujube Slices through Molecular Sensory Science Approaches.

To discriminate the aroma-active compounds in dried jujube slices through microwave-dried treatments and understand their sensory attributes, odor activity value (OAV) and detection frequency analysis (DFA) combined with sensory analysis and analyzed through partial least squares regression analysis (PLSR) were used collaboratively. A total of 21 major aromatic active compounds were identified, among which 4-hexanolide, 4-cyclopentene-1,3-dione, 5-methyl-2(5H)-furanone, 4-hydroxy-2,5-dimethyl-3(2H)furanone, 3,5-dihydroxy-2-methyl-4-pyrone were first confirmed as aromatic compounds of jujube. Sensory evaluation revealed that the major characteristic aromas of dried jujube slices were caramel flavor, roasted sweet flavor, and bitter and burnt flavors.

A one-step base-free synthesis of -arylamides modified pivaloyl mixed anhydride mediated amide coupling.

Pivalic anhydride is shown to be an effective reagent for direct amidation of carboxylic acids with -alkyl anilines. The only by-product of this reaction is nontoxic pivalic acid, which can be easily removed by aqueous workup. The reactions are conducted under mild conditions and found to be compatible with a range of carboxylic acids, including aromatic, heterocyclic, acrylic, and aliphatic carboxylic acids and amino acids generating the desired amides in short reaction times.

Complementary Oxidative Generation of Iminyl Radicals from α-Imino-oxy Acids: Silver-Catalyzed C-H Cyanoalkylation of Heterocycles and Quinones.

A complementary and general strategy for the oxidative generation of iminyl radicals from the readily available α-imino-oxy acids has been established through silver-catalyzed decarboxylation. To demonstrate its synthesis utility, the direct C-H cyanoalkylation of heterocycles and quinones with cyclic α-imino-oxy acids via the iminyl radical-mediated C-C bond cleavage is developed. This cost-effective method takes place under mild reaction conditions and exhibits a broad substrate scope.

General 5-Halomethyl Isoxazoline Synthesis Enabled by Copper-Catalyzed Oxyhalogenation of Alkenes.

A general and efficient oxyhalogenation of unsaturated ketoximes has been achieved through copper catalysis with diethyl bromomalonate, N-chlorosuccinimide, and N-iodosuccinimide, yielding 5-chloromethyl, 5-bromomethyl, and 5-iodomethyl isoxazolines in good to excellent yields.

Metal-free TBAI-catalyzed arylsulfonylation of activated alkenes with sulfonylhydrazides.

An efficient metal-free oxidative arylsulfonylation of α,β-unsaturated imides with sulfonylhydrazides leading to isoquinoline-1,3(2H,4H)-dione derivatives has been developed. The procedure involves the generation of sulfonyl radicals via cleavage of the S-N bond of sulfonylhydrazides with sulfonylation and C-H functionalization. The protocol uses the economical and environmentally friendly TBAI-TBHP catalytic system, and the corresponding isoquinoline-1,3(2H,4H)-diones with various functional groups were obtained in moderate to good yields.

A rapid and effective approach for on-site assessment of total carotenoid content in wolfberry juice during processing.

Background: Carotenoid content analysis in wolfberry processed products has mainly focused on the determination of zeaxanthin or zeaxanthin dipalmitate, which cannot indicate the total carotenoid content (TCC) in wolfberries.

Results: We have exploited an effective approach for rapid extraction of carotenoid from wolfberry juice and determined TCC using UV-visible spectrophotometry. Several solvent mixtures, adsorption wavelengths of carotenoid extracts and extraction procedures were investigated.

Preparation of silica-based nanoparticle having surface-bound octanoyl-aminopropyl moieties and its applications for the capillary electrochromatography separation of charged and neutral compounds.

A kind of novel amphiphilic silica-based nanoparticle having surface-bound octanoyl-aminopropyl moieties (OA-NP) with the diameter of ~250 nm was successfully prepared and characterized by elemental analysis, Fourier transform infrared spectrometry. The potential use of OA-NP as pseudostationary phase in capillary electrochromatography for the separation of aromatic acids, basic, and neutral compounds was investigated. Five aromatic acids were separated rapidly with high column efficiency as they migrate in the same direction with the EOF under optimum experimental conditions.

Monitoring supported-nanocluster heterogeneous catalyst formation: product and kinetic evidence for a 2-step, nucleation and autocatalytic growth mechanism of Pt(0)n formation from H2PtCl6 on Al2O3 or TiO2.

A pressing problem in supported-metal-nanoparticle heterogeneous catalysis--despite the long history and considerable fundamental as well as industrial importance of such heterogeneous catalysts--is how to monitor such catalysts' formation more routinely, rapidly, and in real time. Such information is needed to better control the size, shape, composition, and thus resultant catalytic activity, selectivity, and lifetime of these important catalysts. To this end, a study is reported of the formation of supported Pt(0)(n) nanoparticles by H(2) reduction of H(2)PtCl(6) on Al(2)O(3) (or TiO(2)) to give 6 equivalents of HCl plus supported Pt(0)(n)/Al(2)O(3) (or Pt(0)(n)/TiO(2)), all while in contact with a solution of EtOH and cyclohexene.