Search results for "cyclic"
showing 10 items of 2439 documents
The use of metallocenic esters of n-hydroxysuccinimide for metallohapten synthesis
1991
Different organometallic markers have been described in a new technique for the labelling of many drugs. Thus metallocenic esters of [M = (;CO)3CrC6H5; (;CO)3CrC6H5(;CH2)3; η-C5H5FeC5H4; (;CO)3MnηC5H4; (;CO)3MnηC5H4COCH2CH2; ηC5H4(;ηC5H5)Co+PF−6] react with primary or secondary amine drugs [DRUGNHR] for a psychostimulant drug: amphetamine; tricyclic antidepressants—desipramine and nortriptyline; a vasodilator—histamine; an adrenergic substance—norfenefrine; and for a central stimulant—meth-amphetamine, to give the metallohaptens MCON(;R)—DRUG. All these compounds have been fully characterized by different analytical methods and have potentialities for biological assays. This synthetic route…
Sesquiterpene lactones from Artemisia lucentica
1997
Abstract The aerial parts of Artemisia lucentica yielded, in addition to several known compounds, a bicyclic monoterpene ketone, two germacranolides, an eudesmanolide, a 10- epi neudesmanolide, a 2-norelemanolide and three bisabolene derivatives. The stereochemistry of a germacranolide, described as 2α-hydroxyartemorin in a previous investigation of the species, has now been corrected and the compound has been renamed lucentolide.
Chlorine loss from polyvinylchloride under neutron irradiation
1997
PVC samples were irradiated for 1 hour with a thermal neutron flux of Φ th =4.71·1011n·cm−2·s−1 and the chlorine lost during irradiation was measured by γ-ray spectrometry. About 15% of loss of chlorine has been observed for untreated samples while samples heated to temperatures of 60 and 80°C for one minute before irradiation have been found to loose about 8% and 3%, respectively. The results indicate an influence of the polymer structure on the release of chlorine.
The effect of pH on polymorph formation of the pharmaceutically active compound tianeptine.
2012
The anti-depressant pharmaceutical tianeptine has been investigated to determine the dynamics of polymorph formation under various pH conditions. By varying the pH two crystalline polymorphs were isolated. The molecular and crystal structures have been determined to identify the two polymorphs. One polymorph is an amino carboxylic acid and the other polymorph is a zwitterion. In the solid state the tianeptine moieties are bonded through hydrogen bonds. The zwitterion was found to be less stable and transformed to the acid form. During this investigation an amorphous form was identified.
Nonsteroidal Antiinflammatory Agents, XVIII: C-5 Functionalized 6,7-Diphenyl-2,3-dihydro-1H-pyrrolizines as Inhibitors of Bovine Cyclooxygenase and 5…
1994
6-(4-Chlorophenyl)-7-phenyl-2,3-dihydro-1H-pyrrolizines with functional groups at position 5 of the heterocyclic moiety were synthesized and tested. To determine their antiinflammatory activity bovine blood was used as enzyme source for the cyclooxygenase and 5-lipoxygenase, respectively. The iminoxy acetic acid derivative and the iminotetrazole selectively inhibit the 5-lipoxygenase, all the other compounds show medium or low affinity to the active sites of cyclooxygenase and 5-lipoxygenase. In general all compounds inhibit 5-lipoxygenase more effectively than cyclooxygenase. Concerning the inhibition of 5-lipoxygenase the most active compounds found are equipotent to the corresponding pro…
Isolation of Alkaloids from Cultured Hybrid Cells of Rauwolfia serpentina*Rhazya stricta.
1996
Two monoterpenoid indole alkaloids and four β-carbolines were isolated from a hydrid cell suspension culture generated from two Apocynaceous plants, Rauwolfia serpentina Benth. and Rhazya stricta Decaisne. This indicates that the function of alkoloid biosynthesis is retained after hybrid formation and that alkaloids not previously detected in the parental plants or cell cultures are formed.
Zur protonenkatalysierten elektrophilen substitution von 2,3-dimethylindol mit arylaldehyden: C6-regioselektivität am indol-gerüst
1986
The proton catalyzed reaction of 2,3-dimethylindole (1) with several arylaldehydes 2 yields the 6,6′bisindolylarylmethanes 5 regioselectively. No mechanistic information about the predominant attack of the aldehydes on the indole nucleus is obtained, because the reaction proceeds too fast to control. The electron-rich aldehydes, 2,4,6-trimethoxybenzaldehyde and indole-3-carbaldehyde, yield exclusively the 6,6′,6″-trisin-dolylmethane 9. The constitutions of all isolated methanes were elucidated by 400 MHz 1H-nmr spectroscopy.
First Electrophilic Substitutions of 3-Substituted Indoles with Diethoxycarbenium Tetrafluoroborate: Functionalized Indole Derivatives
1990
The indoles 2a-2c react with diethoxycarbenium tetrafluoroborate (1) to furnish the indolecarbaldehydes 3a-3d. In the thermodynamically controlled reaction of 3-methylindole (2a) with 1 the tris(indolyl)methane 4 and diskatole (5), are formed in addition. The limitations of these reactions are discussed and evidence is presented for a C-3-ipso-attack and a Wagner-Meerwein rearrangement, respectively, leading to the formation of 3b or 3d. Erste elektrophile Substitution von 3-substituierten Indolen mit Diethoxycarbenium-Tetrafluoroborat: Funktionalisierte Indol-Derivate Die Indole 2a-2c reagieren mit dem per se synthetisierten Diethoxycarbenium-Tetrafluoroborat (1) zu den Indolcarbaldehyden …
Cyclic voltammetric analysis of pH-dependent complex formation equilibria in anion coordination chemistry
1995
A procedure to analyze pH-dependent complex formation equilibria from cyclic voltammetry is described. Application to adduct formation equilibria between [Fe(CN)(6)](4-) and [Fe(CN)(6)](3-) with different polyammonium receptors is discussed. Extension to the interaction of substrates such as ATP, NAD(+), NADP(+), and carboxylate ions with these receptors by means of competitive interaction with hexacyanoferrate(II) ion is presented.
Electrochemical study on a tricyclic 1,1,1-tricar-bonyl-2,3-1 diazaferrole derivative. II. Activation of carbon monoxide replacement by electron tran…
1986
Etudes, par voltammetrie cyclique, de la reduction electrochimique du complexe de diazaferratricyclodecene, en presence de P(OMe) 3