Search results for "stereochemistry"
showing 10 items of 4831 documents
1-{3-[(7-Fluoro-9H-pyrimido[4,5-b]indol-4-yl)(methyl)amino]piperidin-1-yl}propan-1-one
2021
The title compound, C19H22FN5O, has been synthesized as an inhibitor of glycogen synthase kinase-3β. Two molecules interact via two N—H...N hydrogen bonds, forming centrosymmetric dimers.
Unexpected behaviour of copper(I) towards a tridentate Schiff base: Synthesis, structure and properties of new Cu(I)-Cu(II) and Cu(II) complexes
2001
cited By 17; International audience; The reaction of CuBr with 2,6-bis[1-(2,6-diisopropylphenylimino)ethyl]pyridine L afforded a new Cu(I)-Cu(II) derivative [CuBrL]2[Cu2Br4] (1), while the reaction of [Cu(CH3CN)4]PF6 with L in THF yielded the new Cu(I) compound CuL(THF)(CH3CN)PF6 (2). Derivative 2 further reacted with halogenated solvents to yield halogeno-Cu(II) salts, [CuClL]PF6 (3) using CHCl3 and [CuBrL]Br3 (4) using CHBr3. Compounds 1, 3 and 4 have been fully characterised by X-ray crystallography; they contain essentially similar [CuXL]+ cations with a square planar copper(II) co-ordination. However, the structure of compound 1 must be viewed as built of tetranuclear units since two […
Crystal structure of 5′′-benzylidene-1′-methyl-4′-phenyltrispiro[acenaphthylene-1,2′-pyrrolidine-3′,1′′-cyclohexane-3′′,2′′′-[1,3]dioxane]-2,6′′-dione
2016
In the title trispiro compound, both the methyl-substituted pyrrolidine and dioxalane rings adopt a twist conformation. The cyclopentanone ring of the acenapthylen-1-one system adopts flattened envelope conformation, and the cyclohexanone attached to the dioxalane ring adopts boat conformation. In the crystal, centrosymmetrically related molecules are linked into dimers forming rings of (10) graph-set motif, which are further connected into chains parallel to the b axis by C—H⋯O contacts forming rings of (8) graph-set motif.
A new member of the fusaricidin family – structure elucidation and synthesis of fusaricidin E
2017
Two hitherto unknown fusaricidins were obtained from fermentation broths of three Paenibacillus strains. After structure elucidation based on tandem mass spectrometry and NMR spectroscopy, fusaricidin E was synthesized to confirm the structure and the suggested stereochemistry. The synthesis was based on a new strategy which includes an efficient access to the 15-guanidino-3-hydroxypentadecanoyl (GHPD) side chain from erucamide.
Mononuclear rearrangements of heterocycles in water/β-CD: information on the real site of reaction from structural modifications of substrates and fr…
2007
Abstract The effect of β-cyclodextrin (β-CD) on the reactivity in the base-catalyzed pathway for the rearrangement in water of some ( Z )-hydrazones of 3-benzoyl-1,2,4-oxadiazoles ( 1b – f ) into the relevant triazoles ( 2b – f ) was investigated, finding different behavior as a function of the proton concentration. ESIMS and 1 H NMR data evidence the formation of host – guest complexes. The whole of the experimental and calculated (MM2) data enabled us to draw some intriguing conclusions concerning the influence of the structures of the substrates and the nature of the formed host – guest complexes on the real site of the reaction.
Metall-π-Komplexe von Benzolderivaten, XII Hyperfeinstruktur und Linienbreiten in den ESR-Spektren methylierter und deuterierter Bis(η-benzol)chrom(I…
1979
Die vollstandige Reihe der Methyl-Substitutionsprodukte des Bis(η-benzol)chrom(I)+·-Radikalkations sowie ausgewahlte deuterierte Derivate desselben wurden in Losung und in glasartig erstarrtem Medium ESR-spektroskopisch untersucht. 1H-, 2D- und 53Cr-Hyperfeinparameter werden mitgeteilt und das Proton/Deuteron-Kopplungskonstantenverhaltnis wird diskutiert. Die Betrage von a(1HAren) und a(1HMethyl) variieren innerhalb enger Grenzen (3,454,15 bzw. 0,50,7 G), wobei a(1HAren) mit zunehmendem Methylierungsgrad zunimmt. Um die Konformationsabhangigkeit von a(1HMethyl) zu studieren, werden die ESR-Spektren von (η12-[2.2]Paracyclophan)-chrom(I)+·, 21+·, und Bis(1,4-dimethyl-η6-benzol)chrom(I)+·, 5+·…
Spectroscopic characterization and biological activity ofL-methionyl-L histidinato complexes of R2Sn(IV) ions (R?=?Me, nBu, Ph) and X-ray structure o…
2000
Complexes of L-methionyl-L-histidine (H2MetHis) with R2Sn(IV) ions (R = Me, nBu, Ph) have been synthesized. The crystal and molecular structures of Me2SnMetHis·0.5MeOH have been determined by X-ray diffraction. The title compound contains two crystallographically independent molecular units possessing the same trigonal-bipyramidal geometry at tin, each dimethyltin(IV) moiety being coordinated by the terminal amino nitrogen, deprotonated peptide nitrogen and terminal carboxylate group, neither the imidazole nor thioether groups being involved in bonding. IR spectroscopy was used to probe the structure of the complexes in the solid state, and the structure in solution (CD3OD) was assessed by …
Toward Anticancer Immunotherapeutics: Well-Defined Polymer-Antibody Conjugates for Selective Dendritic Cell Targeting
2014
This paper describes the synthesis of semitelechelic maleimide-modified N-(2-hydroxypropyl)methacrylamid) (HPMA) based polymers of narrow dispersity that can be conjugated e.g. to anti-DEC-205 antibodies affording "star-like" topologies (one antibody decorated with several polymer chains). FCS revealed a hydrodynamic diameter of R(h) = 7.9 nm and SEC narrow dispersity (1.45). Primary in vitro studies with bone marrow derived dendritic cells (DC) show higher cellular binding and uptake rates compared to control samples. Moreover, incubating these conjugates to primary splenocytes demonstrates a much higher affinity to the primary DCs than to any other immune cell population within the splee…
Understanding the stereo- and regioselectivities of the polar Diels-Alder reactions between 2-acetyl-1,4-benzoquinone and methyl substituted 1,3-buta…
2009
The polar Diels–Alder (DA) reactions of 2-acetyl-1,4-benzoquinone (acBQ) with methyl substituted 1,3-butadienes have been studied using DFT methods at the B3LYP/6-31G(d) level of theory. These reactions are characterized by a nucleophilic attack of the unsubstituted ends of the 1,3-dienes to the β conjugated position of the acBQ followed by ring-closure. The reactions present a total regioselectivity and large endo selectivity. The analysis based on the global electrophilicity of the reagents at the ground state, and the natural bond orbital (NBO) population analysis at the transition states correctly explain the polar nature of these cycloadditions. The large electrophilic character of acB…
Population analysis of pair densities. A study on cyclic systems
2000
Abstract Pair population analysis seems a reliable method for evaluating atomic valency states and bond orders from the MO wavefunction of molecular systems. A test on some cyclic organic systems was performed. The results confirm the capability of the method to provide a correct description of the molecules in terms of simple VB approach.