Search results for "medicinal"
showing 10 items of 2966 documents
Synthesis and Characterization of Copper Complexes Containing the Tripodal N7 Ligand Tris{2-[(pyridin-2-ylmethyl)amino]ethyl}amine (=N′-(Pyridin-2-yl…
2005
The stability constants of the CuII chelates with the tripodal heptadentate ligand tris{2-[(2-pyridylmethyl)amino]ethyl}amine (=N′-(pyridin-2-ylmethyl)-N,N-bis{2-[(pyridin-2-ylmethyl)amino]ethyl}ethane-1,2-diamine; tpaa), determined by potentiometry and UV spectrometry, show the formation of [Cu(tpaaH)]3+ and [Cu(tpaa)]2+ species. In the solid state, two mononuclear CuII compounds, [Cu(tpaa)](PF6)2 (1) and [Cu(tpaaH)](ClO4)3⋅H2O (2), and one trinuclear [Cu3(tpaa)2(ClO4)2](ClO4)4⋅2 H2O (3) complex were isolated and characterized by IR, UV/VIS, and EPR spectroscopy. An X-ray structure of the mononuclear protonated complex 2 shows that the Cu2+ ion has a distorted square-pyramidal geometry (τ=…
Natural substances (acetogenins) from the family Annonaceae are powerful inhibitors of mitochondrial NADH dehydrogenase (Complex I).
1994
Natural products from the plants of the family Annonaceae, collectively called Annonaceous acetogenins, are very potent inhibitors of the NADH-ubiquinone reductase (Complex I) activity of mammalian mitochondria. The properties of five of such acetogenins are compared with those of rotenone and piericidin, classical potent inhibitors of Complex I. Rolliniastatin-1 and rolliniastatin-2 are more powerful than piericidin in terms of both their inhibitory constant and the protein-dependence of their titre in bovine submitochondrial particles. These acetogenins could be considered therefore the most potent inhibitors of mammalian Complex I. Squamocin and otivarin also have an inhibitory constant …
Formation of New η5-Rhodium(III) Complexes from η5-Rh(I) Rhodacarborane-Containing Charge-Compensated Ligands
2004
A series of new Rh(I) half-sandwich complexes of formula [3,3-(PPh 3 ) 2 -8-L-closo-3,1,2-RhC 2 B 9 H 1 0 )] (L = SMe 2 (2a), SEt 2 (2b), S(CH 2 ) 4 (2c), SEtPh (2d)) and [1-Me-3,3-(PPh 3 ) 2 -8-L-closo-3,1,2-RhC 2 B 9 H 9 )] (L = SMe 2 (2e), SEt 2 (2f)) have been prepared by reaction of the respective monoanionic charge-compensated ligands [10-L-nido-7,8-C 2 B 9 H 1 0 ] - and [7-Me-10-L-7,8-C 2 B 9 H 9 ] - with [RhCl(PPh 3 ) 3 ]. Complex [3,3-(cod)-8-SMe2-closo-3,1,2-RhC 2 B 9 H 1 0 ] (3) has also been prepared by reaction of K[10-SMe 2 -nido-7,8-C 2 B 9 H 1 0 ] with [RhCl(cod)] 2 . Rh(I) complexes 2a-d may be easily oxidized to the corresponding Rh(III) complexes 4a-d under N 2 atmosphere…
Three New Triterpene Saponins from Two Species of Carpolobia
2002
Three new acetylated triterpene saponins 1-3 were isolated from the roots of Carpolobia alba and C. lutea. Their structures were established mainly by 2D NMR techniques as 3-O-beta-D-glucopyranosylpresenegenin-28-O-beta-D-galactopyranosyl-(1-->4)-[beta-D-xylopyranosyl-(1-->3)]-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-(3,4-di-O-acetyl)-beta-D-fucopyranosyl ester, 3-O-beta-D-glucopyranosylpresenegenin-28-O-beta-D-galactopyranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->3)]-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-(3,4-di-O-acetyl)-beta-D-fucopyranosyl ester, and 3-O-beta-D-glucopyranosylpresenegenin-28-O-beta-D-xylopyranosyl-(1-->4)-[beta-D-apiofuranosyl…
Glandulosides A-D, triterpene saponins from Acanthophyllum glandulosum.
2004
Four novel triterpenoid saponins, glandulosides A (1), B (2), C (3), and D (4), together with two known saponins (5 and 6) have been isolated from the roots of Acanthophyllum glandulosum. Their structures were elucidated using a combination of homo- and heteronuclear 2D NMR techniques (COSY, TOCSY, NOESY, HSQC, and HMBC) and by FABMS. The new compounds were characterized as 23-O-beta-D-galactopyranosylgypsogenic acid-28-O-beta-D-glucopyranosyl-(1-->3)-[beta-d-galactopyranosyl-(1-->6)]-beta-D-galactopyranoside (1), 3-O-beta-D-galactopyranosyl-(1-->2)-[beta-D-xylopyranosyl-(1-->3)]-beta-D-glucuronopyranosylgypsogenin-28-O-beta-D-xylopyranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-alpha-l-rhamn…
Antiproliferative Oleanane Saponins from Meryta denhamii
2008
Eight new oleanane saponins (1- 8) together with four know saponins (9-12) were isolated from the aerial parts of Meryta denhamii. Their structures were elucidated by 1D and 2D NMR experiments including 1D TOCSY, DQF-COSY, ROESY, HSQC, and HMBC spectroscopy, as well as ESIMS analysis. The antiproliferative activity of all compounds was evaluated using three murine and human cancer cell lines: J774.A1, HEK-293, and WEHI-164.
Dihydroisocoumarins, Naphthalenes, and Further Polyketides from Aloe vera and A. plicatilis: Isolation, Identification and Their 5-LOX/COX-1 Inhibiti…
2021
The present study aims at the isolation and identification of diverse phenolic polyketides from Aloe vera (L.) Burm.f. and Aloe plicatilis (L.) Miller and includes their 5-LOX/COX-1 inhibiting potency. After initial Sephadex-LH20 gel filtration and combined silica gel 60- and RP18-CC, three dihydroisocoumarins (nonaketides), four 5-methyl-8-C-glucosylchromones (heptaketides) from A. vera, and two hexaketide-naphthalenes from A. plicatilis have been isolated by means of HSCCC. The structures of all polyketides were elucidated by ESI-MS and 2D 1H/13C-NMR (HMQC, HMBC) techniques. The analytical/preparative separation of 3R-feralolide, 3′-O-β-d-glucopyranosyl- and the new 6-O-β-d-glucopyranosyl…
Diorganotin(IV) Complexes of Methyl 2-{[(E)-8-Oxo-5, 8-dihydroquinolin-5-ylidene]hydrazino}benzoate
2012
Three cis-bis{5-[(E)-2-(2-carbomethoxyphenyl)-1- diazenyl]quinolinolato}-diorganotin(IV), R2Sn(L)2, complexes [R = Me (1), Ph (2) and Bz (3)] were synthesized and characterized by 1H-, 13C-, 119Sn- NMR, IR, and 119Sn Mössbauer spectroscopic techniques in combination with elemental analysis. The structure of diphenyltin(IV) complex Ph2Sn(L)2 (2) was determined by single-crystal X-ray crystallography as its tri-benzene solvate. Each complex was found to adopt a distorted cis-R2 octahedral arrangement around the tin atom with the quinolinolato ligands being N,O-chelating; the oxygen atoms are trans to each other. The complexes retain their solid- state structure in non-coordinating solvents as…
Modeling the Geometric, Electronic, and Redox Properties of Iron(III)-Containing Amphiphiles with Asymmetric [NN′O] Headgroups
2011
Two iron(III)-containing amphiphiles 1 and 2 have been synthesized with the [NN'O] ligands HL(tBu-ODA) (2-((octadecyl(pyridin-2-ylmethyl)amino)methyl)-4,6-di-tert-butylphenol) and HL(I-ODA) (2-((octadecyl(pyridin-2-ylmethyl)amino)methyl)-4,6-diiodophenol), respectively. Compound 1 is monometallic, whereas EXAFS data suggest that 2 is a mixture of mono- and bimetallic species. The archetypical [Fe(III)(L(NN'O))(2)](+) complexes 3-9 have been isolated and characterized in order to understand the geometric, electronic, and redox properties of the amphiphiles. Preference for a monometallic or bimetallic nuclearity is dependent on (i) the nature of the solvent used for synthesis and (ii) the typ…
Mono- and Bimetallic Zwitterionic Chromium(0) and Tungsten(0) Allenyls
2015
A series of stable chiral (racemic), formally neutral, zwitterionic mono- and bimetallic M(CO)5[C(OEt)═C═CR(NHC)] (M = Cr, W) σ-allenyls are ready available by the addition of N-heterocyclic carbenes (NHCs) to Cr(0) and W(0) alkynyl Fischer carbene complexes. Different classes of NHCs, (e.g., 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene, 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene, and their six- and seven-membered analogues and 1,3-bis(dimethyl)imidazol-2-ylidene) were employed as nucleophiles in these C-C bond-forming reactions yielding the novel complexes in essentially quantitative yields. A systematic experimental and computational study of the electronic properties of the C…