Phytochemical constituents of Asparagus adscendens and Asparagus racemosus are being reported in the present communication. Two new sarsasapogenin glycosides have been isolated, one from each of the species. Structure elucidation of 1 and 10 has been accomplished through the extensive use of 1Dand 2D-NMR experiments including H-H (DQFCOSY), H-C (HMQC, HMBC) spectroscopy along with mass spectros...

achillea tenuifolia lam (asteraceae) afforded a methanolic extract from which after fractionation in solvents with different polarities two known flavones 3’, 5- dihydroxy- 4’, 6, 7- trimethoxy flavone (eupatorine, compound 3), 5- hydroxy- 3’, 4’, 6, 7- tetramethoxyflavone (compound 4), besides stearic acid (compound 1 ), lupeol (compound 2), daucosterol (β- sitosterol 3-o- β- d- glucopyranosid...

The structural elucidation of 2α-cyclodextrin/1-octanethiol, 2α-cyclodextrin/1-octylamine and 2α-cyclodextrin/1-nonanoic acid inclusion complexes by nuclear magnetic resonance (NMR) spectroscopy and molecular modeling has been achieved. The detailed spatial configurations are proposed for the three inclusion complexes based on 2D NMR method. ROESY experiments confirm the inclusion of guest mole...

This paper highlights the use of two-dimensional (2D) solid-state NMR correlation techniques to probe the chemical homogeneity of organically modified silicate networks. Specifically, 29Si{1H} heteronuclear correlation (HETCOR) NMR experiments have revealed the spatial proximity of the two types of Si units present in a gel obtained from co-hydrolysis of methyldiethoxysilane and triethoxysilane...

2D NMR relies on monitoring systematic changes in the phases incurred by spin coherences as a function of an encoding time t(1), whose value changes over the course of independent experiments. The intrinsic multiscan nature of such protocols implies that resistive and/or hybrid magnets, capable of delivering the highest magnetic field strengths but possessing poor temporal stabilities, become u...

The ethyl acetate partition of dried methanolic extract of aerial parts of Euphorbia microsciadia (Euphorbiaceae) afforded three pentacyclic triterpenes, betulinic acid (1) from lupane type, oleanolic acid (2) from oleane type and ursolic acid (3) from ursane type triterpenes that are reported for the first time in this plant. These three compounds were structurally compared through their mass ...

A novel constituent of bacterial polysaccharides, 2,3,4-triacetamido-2,3,4-trideoxy-L-arabinose, was found in the O-specific polysaccharide from the lipopolysaccharide of Psychrobacter cryohalolentis K5(T) and identified by 1D and 2D (1)H and (13)C NMR studies of the polysaccharide and a disaccharide obtained by solvolysis of the polysaccharide with triflic acid. The following structure of the ...

Natural products provide excellent potential leads for drug development because of their chemical diversity and biological functionality. However, the productivity of discovery of new, pharmacologically active natural products has traditionally been low due to inherent difficulties and costs associated with extract dereplication, i.e., isolation, purification and structure elucidation of indivi...

Friedelin (1), 3beta-friedelinol (2), 28-hydroxyfriedelin (3), 16alpha-hydroxyfriedelin (4), 30-hydroxyfriedelin (5) and 16alpha,28-dihydroxyfriedelin (6) were isolated through fractionation of the hexane extract obtained from branches of Salacia elliptica. After a week in CDCl(3) solution, 16alpha-hydroxyfriedelin (4) reacted turning into 3-oxo-16-methylfriedel-16-ene (7). This is the first re...