Two new chalcones from Shuteria sinensis

Two new chalcones, 2′,3,4,4′-tetrahydroxy-2-prenylchalcone (1) and 3-methoxy-2′,4,4′-trihydroxy-2-prenylchalcone (2), together with two known compounds, munsericin (3) and 3,4-dihydroxylonchocarpin (4), were isolated from the ethanol extract of the whole plant of Shuteria sinensis. Their structures were identified by spectroscopic analysis methods, such as 1D and 2D NMR, along with HR-MS data. Glucose metabolism activity of four compounds was tested, compounds 3 and 4 showed effect on the glucose consumption of insulin-resistant HepG2 cells.     

Isolation and Characterization of Secondary Metabolites from Rhododendron microphyton

Four new iridoids, incarvoids D–F ( 1 – 3 , resp.) and incarvoid B 9‐O‐β‐D ‐glucopyranoside ( 4 ), and one new monoterpenoid, argutoid B ( 5 ), along with 14 known compounds, were isolated from Rhododendron microphyton. Their structures were established by comprehensive 1D‐ and 2D‐NMR spectroscopic analysis.     

Nickel N‐Heterocyclic Carbene Catalyzed CC Bond Formation: A New Route to Aryl Ketones

A novel nickel N‐heterocyclic carbene catalyzed cross‐coupling reaction of aryl aldehydes with boronic esters for the synthesis of aryl ketones was developed. This reaction provides a mild, practical method toward aryl ketones, which are versatile intermediates and building blocks in organic synthesis.     

Colorimetric enantiodiscrimination of mandelic acid by indicator displacement assay

The colorimetric enantiodiscrimination between mandelic acid and L-proline-Cu(II) is exploited to develop enantioselective indicator displacement assays. The sensitivity of the assay could be tuned by using a colorimetric indicator. The chromophoric ligand, pyrocatechol violet, effectively competes with the mandelic acid guest for open coordination sites on L-proline-Cu(II). The DA could be increased to 0.12 by changing the ratio of(+)- and(à)-mandelic acid concentrations that were found to be optimal from the displacement experiments. The resultant enantiomer excess versus DA relationship is linear. From the calibration curves, the absorbance values of the unknowns may be calculated for the enantiomeric excess value and the colorimetric enantiodiscrimination of mandelic acid can thus be obtained.     

A Rhodamine-based fluorescent sensor for chromium ions and its application in bioimaging

A rhodamine-based sensor (1) has been developed for the detection of chromium ions. Cr³⁺-induced opening of the rhodamine spirocycle in sensor (1) led to the distinct colorimetric and fluorescence responses. Among all the tested ions, only Cr³⁺ generated a significant fluorescence enhancement of up to 13-fold, which indicated the high selectivity of 1. Sensor (1) was successfully applied in the in vivo fluorescence imaging of Cr³⁺ in C. elegans. The results provided solid evidences for the future estimation of Cr³⁺ in environmental applications and tobacco samples.     

3D Chiral Nanoporous Metal–Organic Framework for Chromatographic Separation in GC

Metal–organic frameworks (MOFs) have received great attention as stationary phases in chromatographic separation technology because of their unusual properties such as high surface areas, fascinating structures, and excellent chemical and thermal stability. A chiral MOF, [(CH₃)₂NH₂][Cd(bpdc)_1.5]·2DMA, possesses a unique chiral nanotube motif built from the covalent linkage of homochiral nanotubes made up of octuple helices. Here, we report the fabrication of a three-dimensional (3D) chiral nanoporous MOF-coated capillary column (2 m long × 75 μm i.d.) for capillary gas chromatographic separation of racemates, Grob’s test mixture, normal alkanes, normal alcohols, and isomers. The MOF-coated capillary column offered good separation efficiency (2,180 plates m^?1), which was measured using n-dodecane as the analyte at 120 °C. The relative standard deviations of repeatability for citronellal on MOF-coated capillary column were 0.23 and 2.1 % for retention time and peak area, respectively. The results demonstrated that the capillary column exhibited excellent selectivity and separation ability toward Grob’s test mixture, normal alkanes, normal alcohols and isomers, especially for racemates.     

Evollionines A–C,Three New Alkaloids Isolated from the Fruits of Evodia rutaecarpa

A phytochemical study of the CHCl₃ extract of the dried unripe fruits of Evodia rutaecarpa (Juss. ) Benth. (Rutaceae) resulted in the isolation of three new alkaloids, evollionines A–C ( 1 – 3 , resp.), together with two known compounds, evodianinine and wuzhuyumide I. The structures of the new compounds were elucidated on the basis of detailed spectroscopic evidence and confirmed in the case of compound 1 by single‐crystal X‐ray analysis.