Two indole alkaloids, Vincamine 1 and 14-epi-vincamine 2 were isolated here for the first time from Ambelania occidentalis. The structures of these compounds were elucidated by one and two dimension NMR and MS spectroscopy.

Diabetes mellitus is the most common endocrine disorder characterized by hyperglycemia resulting from defects in insulin secretion or insulin action. The present study was designed to investigate the antidiabetic effects of vincamine, one of the monoterpenoid indole alkaloid, in streptozotocin-i...

A new convenient route to synthesize 1,10-seco-triterpenoids from allobetulin was demonstrated. Stereoisomerism of starting oleanane 1-oximes was determined by X-ray crystallography and additionally confirmed by the structure of the obtained Beckmann rearrangement products. Absolute configuratio...

A variety of allobetulin derivatives was synthesized from allobetulin or allobetulone. These compounds were screened for their cytotoxic activity using a photometric SRB assay employing six different human tumor cell lines. In summary, opening of ring A of allobetulin in general lowers the cytot...

Catalytic hydrogenation of terpenes constitutes one of the most interesting reactions in the transformation of natural products. One of the key goals in this synthesis is the selective hydrogenation of the CO bond for obtaining biologically active epimeric alcohols. In the present work, the use ...

Lupeol has been shown with anti-inflammation and antitumor capability, however, the poor bioavailability limiting its applications in living subjects. Lupeol acetate (LA), a derivative of lupeol, shows similar biological activities as lupeol but with better bioavailability. Here RAW 264.7 cells ...

Glycosyltransferase (GT) can convert flavonoids, alkaloids, and terpenoids into glycosylated forms. An oleandomycin glycosyltransferase, “OleD” GT from Streptomyces antibioticus was exploited for the glycosylation of amentoflavone. The OleD was functionally expressed in Escherichia coli BL21 (...

A biflavonoid, amentoflavone isolated from Nandina domestica and characterized by NMR spectral-data analyses was assessed for its antioxidant, and antibacterial potential in vitro and in food-model systems. Amentoflavone exhibited potent antioxidant ability (19.21–75.52%) on scavenging DPPH, AB...

The aminolysis of ethyl acetate was promoted significantly via continuous reaction in a tubular reactor. N-propylacetamide was thus synthesized without presence of solvent and catalyst. The optimum conditions were obtained as follows: the reaction temperature is 218 °C, the reaction pressure is...

Density and viscosity for mixtures of alkyl esters with alcohols is essential not only for simulation and optimization of diesel engine but also for the understanding of the interactions between them. The new densities of binary mixtures of methanol with three fatty acid ethyl esters (ethyl capr...

A new group of derivatives of salicylic acid containing NO-donor furoxans, and the related des-NO-furazans, were synthesized and evaluated as new aspirin-like molecules. Their stability was assessed in acid (pH 1) and physiological solutions (pH 7.4), and in human serum. No compound exhibited CO...

An enantioconvergent route for natural form of ethyl shikimate was achieved from Diels–Alder adduct of furan and acryloyl chloride. The key step was a highly enantioselective (E >500) and efficient acetylation of ethyl (3R*,4S*,5S*)-5-hydroxy-3,4-isopropylidenedioxycyclohex-1-enecarboxylate, wh...

Ethyl 3-iodo-4,4,4-trifluoro-2(Z)-butenoate (2) was regio- and stereo-specific prepared from ethyl 4,4,4-trifluoro-2-butynote (1). The Sonogashira reaction of 2 with terminal alkynes afforded the (2Z)-en-4-ynoic acid derivatives containing trifluoromethyl group (4). © 1997 Elsevier Science Ltd.

The cis-[PtCl2(PPh3)2]/SnCl2 bimetallic system is highly active and regioselective in the hydroformylation of ethyl 3-butenoate under standard oxo-conditions. Ketones or aromatic hydrocarbons are the best reaction media; ethanol strongly inhibits the catalytic activity. In this solvent the catal...

The relative-rate technique has been used to obtain rates coefficients for the reactions of the unsaturated esters methyl-3,3-dimethyl acrylate, (E)-ethyl tiglate and methyl-3-butenoate with OH radicals and chlorine atoms at (298 ± 2) K in synthetic air at a total pressure of (760 ± 10) Torr. ...

Several aryl 3-methyl-2-butenoate esters upon irradiation lead to the formation of [1,3]-migrated photoproducts, phenol and, surprisingly 2,2-dimethylchroman-4-one derivatives. The starting photochemical reaction takes place from the singlet excited state of the ester and as a total mechanism tw...

Novel non-charged and ionic xylan carbamate (XC) derivatives were synthesized in a modular approach from xylan phenyl carbonates (XPC) as reactive intermediates. XPC with varying degrees of substitution (DS) from 0.5 to 1.9 were converted with different non-ionic primary and secondary amines in ...

Plants of the humid tropics seal their leaf surfaces with hydrophobic waxes to keep them dry and clean by repelling water and diminishing the adhesion of spores of pathogenic and epiphyllous organisms. We investigated the chemical composition and micromorphological structure of waxes of the uppe...

Ferns are known to contain long chain polyunsaturated fatty acids which may provide health benefits. The objective of this study was to investigate ferns of Pacific temperate regions (Far East of Russia and New Zealand) as sources of valuable fatty acids: arachidonic (20:4n-6) and eicosapentaeno...

The purpose of this study was to show how current vegetation in a peatland is imprinted on the lipid fraction of the underlying soil. La Guette is a fen peatland in Central France dominated by Sphagnum spp. and ericaceous shrubs, colonized by sedges (Molinia caerulea) and trees since the 1970s (...