Search results for "Chemical structure"

2017

A new isoflavone, 8-prenylmilldrone (1), and four new rotenoids, oblarotenoids A–D (2–5), along with nine known compounds (6–14), were isolated from the CH2Cl2/CH3OH (1:1) extract of the leaves of Millettia oblata ssp. teitensis by chromatographic separation. The purified compounds were identified by NMR spectroscopic and mass spectrometric analyses, whereas the absolute configurations of the rotenoids were established on the basis of chiroptical data and in some cases by single-crystal X-ray crystallography. Maximaisoflavone J (11) and oblarotenoid C (4) showed weak activity against the human breast cancer cell line MDA-MB-231 with IC50 values of 33.3 and 93.8 μM, respectively.

Isolation, Identification, and Chemical Synthesis of 6α-Hydroxyraumacline: A Novel Alkaloid from CultivatedRauwolfia serpentinaCells

1992

From RAUWOLFIA SERPENTINA cells cultivated in the presence of ajmaline ( 2) the new indole alkaloid, 6alpha-hydroxyraumacline ( 1), was isolated. This alkaloid also occurs in significant amounts in the nutrition medium. A simple chemical synthesis of 1 was developed starting from ajmaline ( 2).

Research Letter: Structural Combination of Established 5-HT2A Receptor Ligands: New Aspects of the Binding Mode

2010

MH.MZ, MDL 100907, and altanserin are structurally similar 4-benzoyl-piperidine derivatives and are well accommodated to receptor interaction models. We combined structural elements of different high-affinity and selective 5-HT(2A) antagonists, as MH.MZ, altanserin, and SR 46349B, to improve the binding properties of new compounds. Three new derivatives were synthesized with a 4-benzoyl-piperidine moiety as the lead structure. The in vitro affinity of the novel compounds was determined by a [³H]MDL 100907 competition binding assay. The combination of MH.MZ and SR 46349B resulted in a compound (8) with a moderate affinity toward the 5-HT(2A) receptor (K(i) = 57 nm). The remarkably reduced af…

New Steroidal Alkaloids from Solanum Hypomalacophyllum

2010

Two new steroidal alkaloids (1-2) have been isolated from the leaves and roots of Solanum hypomalacophyllum Bitter, respectively. Their structures have been elucidated as deacetoxysolaphyllidine-3- O-β-D-glucopyranoside (1) and 4-keto-5,6-dihydro-(20 S)-verazine (2). Furthermore, two known steroidal alkaloids, 20 R-verazine and 20 S-verazine, and the common secondary metabolites oleanolic acid and β-sitosterol were isolated from the roots, whereas deacetoxysolaphyllidine was obtained from the leaves.

Characterization and Decomposition of the Natural van der Waals SnSb2Te4 under Compression

2020

[EN] High pressure X-ray diffraction, Raman scattering, and electrical measurements, together with theoretical calculations, which include the analysis of the topological electron density and electronic localization function, evidence the presence of an isostructural phase transition around 2 GPa, a Fermi resonance around 3.5 GPa, and a pressure-induced decomposition of SnSb2Te4 into the high-pressure phases of its parent binary compounds (alpha-Sb2Te3 and SnTe) above 7 GPa. The internal polyhedral compressibility, the behavior of the Raman-active modes, the electrical behavior, and the nature of its different bonds under compression have been discussed and compared with their parent binary…

Experimental and Theoretical Study of SbPO 4 under Compression

2019

SbPO4 is a complex monoclinic layered material characterized by a strong activity of the non-bonding lone electron pair (LEP) of Sb. The strong cation LEP leads to the formation of layers piled up along the a-axis and linked by weak Sb-O electrostatic interactions. In fact, Sb is 4-fold coordination with O similar to what occurs with the P-O coordination, despite the large difference of ionic radii and electronegativity between both elements. Here we report a joint experimental and theoretical study of the structural and vibrational properties of SbPO4 at high pressure. We show that SbPO4 is not only one of the most compressible phosphates but also one of the most compressible compounds of …

Highly selective and sensitive chromo-fluorogenic detection of the Tetryl explosive using functional silica nanoparticles

2011

Silica nanoparticles containing polyamines and thiol groups have been used as probes for the selective detection of Tetryl. © 2011 The Royal Society of Chemistry.

Determination of the hydrophobicity of organic compounds measured as logPo/w through a new chromatographic method

2009

A new chromatographic method to determine the octanol-water partition coefficient (logP(o/w)) of organic substances is proposed in this paper. This method is based on a previously reported model that relates the retention factor in reversed-phase liquid chromatography with solute (p), mobile phase (P(m)(N)) and stationary phase (P(s)(N)) polarity parameters: logk=(logk)(0)+p(P(m)(N)-P(s)(N)). P(m)(N) values are calculated through expressions that depend only on the organic solvent fraction in the mobile phase. (logk)(0) and P(s)(N) parameters are characteristic of the chromatographic system and are determined from the retention of a selected set of 12 compounds. Then, the p value of a solut…

Influence of nitroreductase and O-acetyltransferase on the mutagenicity of substituted nitrobenzothiophenamines in Salmonella typhimurium.

1999

The mutagenic activity of 17 substituted (aryl)(2-nitrobenzo[b]thiophen-3yl)amines has been evaluated in the Ames test with different isogenic strains of Salmonella typhimurium, that varied in their expression of nitroreductase and O-acetyltransferase. Active derivatives induced frameshift mutations in TA98 strain, and differences in the chemical structure resulted in up to 15-fold changes in mutagenic activity. The non-mutagenic compounds are the unsubstituted parent compound and derivatives with para-chloro, para-fluoro, para-diethylamino, meta-bromo and para-dimethylamino groups. They do not show any activity even in strains with higher level of nitroreductase or O-acetyltransferase. The…

Role of Wood Macromolecules on Selective Sorption of Phenolic Compounds by Wood

2008

Wood is a complex structure of various macromolecules, mainly cellulose, hemicellulose, and lignin. Although the sorption process of some organic compounds by wood has been elucidated, the relative contribution of its different fractions in the sorption mechanism is not clearly determined. Certain works predict the amount of organic compounds sorbed on wood as a direct relationship to its lignin fraction. All wood macromolecules, however, seem to have the capacity to sorb organic compounds. Sorption of phenolic compounds on individual wood macromolecules has been studied and compared to that on wood. Wood-water partition coefficients ( K wood) for phenolic volatiles and their sorption rates…