Bonding a linearly piezoelectric patch on a linearly elastic body

A rigorous study of the asymptotic behavior of the system constituted by a very thin linearly piezoelectric plate bonded on a linearly elastic body supplies various models for an elastic body monitored by a piezoelectric patch.     

Facile and Divergent Synthesis of Lamellarins and Lactam‐Containing Derivatives with Improved Drug Likeness and Biological Activities

With the goal to improve the aqueous solubility of lamellarins, the lactone ring in their skeleton was replaced with a lactam moiety in azalamellarins. However, the reported synthetic route produced such derivatives in very low yields. Hence, this study focused on developing an efficient simplified total synthetic scheme that could furnish both azalamellarins and the parent lamellarins from the same pyrrole ester intermediates. Subsequent comparative profiling revealed that the introduced lactone‐to‐lactam replacement rendered these molecules less lipophilic, whereas their cancer cytotoxicity remained equipotent to that of the parent compounds. Interestingly, their inhibitory activity was significantly enhanced towards the multifaceted GSK‐3β enzyme. Our results clearly demonstrate the therapeutic potential of this promising class of marine‐derived natural products and justify their further development, especially into anticancer agents.     

A new 22,26-seco physalin steroid from Physalis angulata

Abstract

A new 22,26-seco physalin, physalin XI (1) together with 5 known compounds, were isolated from the dichloromethane extract of Physalis angulata L. The structure of isolated compounds was elucidated by spectroscopic analysis. The effects of isolated compounds on in vitro cytotoxicity were investigated. Compound 1 was assessed for its cytotoxicity against cancer cell lines (HepG2, HeLa, HuCCA-1, T47-D and A-549) and a normal cell line (MRC-5), and the result showed that it has no activity. Compounds 2 and 4 are highly toxic to H69AR and MDA-MB-23 cell lines. This property appears to be related to the presence of their conjugated double bond or epoxy groups and is a more reliable indication of toxicity than substitution on C(5)–C(6).     

Synthesis of benzoindoloquinolizines via a Cu(I)-mediated C–N bond formation

An effective synthesis of the multi ring-fused benzoindoloquinolizines has been accomplished by Cu(I)-mediated and MW-assisted C–N_amide bond formation of benzo[a]quinolizin-4-ones. The deamination of tetrahydro-2H-pyrido[2,1-a]isoquinolines was also studied and was found to give benzoquinolizines. The benzo[a]quinolizin-4-ones were prepared based on the annulations of C-1 substituted 3,4-dihydroisoquinolines and azlactones.     

Acetophenone diglycosides from Erythroxylum cambodianum

Two new acetophenone diglycosides, erythroxylosides A and B, were isolated from the aerial portion of Erythroxylum cambodianum together with (+)-catechin, (-)-epicatechin, quercetin 3-O-rutinoside, (3S,5R,6R,7E,9S-megastigman-7-ene-3,5,6,9-tetrol 3-O-beta-D-glucopyranoside and citroside A. The structural elucidations were based on analyses of chemical and spectroscopic data.     

Rapid analysis of clenbuterol, salbutamol, procaterol, and fenoterol in pharmaceuticals and human urine by capillary electrophoresis

Capillary electrophoresis (CE) with UV detection for the simultaneous and short-time analysis of clenbuterol, salbutamol, procaterol, fenoterol is described and validated. Optimized conditions were found to be a 10 mmoll(-1) borate buffer (pH 10.0), an separation voltage of 19 kV, and a separation temperature of 32 degrees C. Detection was set at 205 nm. Under the optimized conditions, analyses of the four analytes in pharmaceutical and human urine samples were carried out in approximately 1 min. The interference of the sample matrix was not observed. The LOD (limits of detection) defined at S/N of 3:1 was found between 0.5 and 2.0 mgl(-1) for the analytes. The linearity of the detector response was within the range from 2.0 to 30 mgl(-1) with correlation coefficient >0.996.     

Synthesis and antibacterial activity of methylated N-(4-N,N-dimethylaminocinnamyl) chitosan chloride

The methylated chitosan containing different aromatic moieties were synthesized by two steps, the reductive amination and the methylation. The chemical structures of all methylated derivatives, methylated N-(4-N,N-dimethylaminocinnamyl) chitosan chloride (MDMCMCh), methylated N-(4-pyridylmethyl) chitosan chloride (MPyMeCh), and N,N,N-trimethyl chitosan chloride (TMChC) were characterized by ATR-FTIR and ¹H NMR spectroscopy. The molecular weights of the methylated chitosan derivatives were determined by gel permeation chromatography. The results revealed that the molecular weights of chitosan and N-aryl chitosan derivatives could be reduced by the methylation process. The degree of N-substitution (DS) and the degree of quaternization (DQ) were calculated by ¹H NMR ranged from 50% to 76%, and 28% to 82%, respectively. The water solubility of the methylated chitosan derivatives decreased with increasing concentration and pH. The antibacterial studies of these methylated chitosan derivatives were carried out by using minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods against Escherichia coli ATCC 25922 (Gram-negative) and Staphylococcus aureus ATCC 6538 (Gram-positive) bacteria. It was found that the MDMCMCh showed higher antibacterial activity than TMChC while MPyMeCh exhibited reduced antibacterial activity against both bacteria at the same DQ level. In comparison to each of the chemical structure, it was found that the antibacterial activity was not only dependent on the DQ but it was also dependent on the positively charged location and the molecular weight.     

A novel approach for the synthesis of lophocladines A, B and C1 analogues

A novel approach for the syntheses of lophocladines A and B has been developed. These compounds were prepared in 4-6 steps with moderate to excellent overall yields. The key step involved the nucleophilic substitution of 4-chloronicotinic acid with the carbanion generated from phenylacetonitrile. Subsequent reduction of the cyano group, lactamization and oxidation furnished lophocladine A in 50% yield over 4 steps. Further amination with various amines led to lophocladine B and its C1 analogues in good yields. In addition, the synthesized compounds were evaluated for their cytotoxicity against leukaemia cells.     

3-Hydroxydihydrobenzofuran glucosides from Gnaphalium polycaulon

A new 3-hydroxydihydrobenzofuran glucoside, gnaphaliol 9-O-β-D-glucopyranoside (2), was isolated from the aerial parts of Gnaphalium polycaulon together with 1-{(2R*,3S*-3-(β-D-glucopyranosyloxy)-2,3-dihydro-2-[1-(hydroxyl methyl)vinyl]-1-benzofuran-5-yl}-ethanone or gnaphaliol 3-O-β-D-glucopyranoside (1), (Z)-3-hexenyl O-β-D-glucopyranoside (3) and adenosine (4). The absolute configurations at C-2 and C-3 positions of compound 1 were determined to be 2R and 3R. The structures of these compounds were elucidated on the basis of their physical and spectroscopic data.