Search results for "solu"
showing 10 items of 7577 documents
Special Calixarenes by Directed Syntheses
1997
The synthesis of special calixarenes and calixarene-like macrocyclic compounds via stepwise procedures and fragment condensation is reviewed. Among the compounds available are exo- and endo-calixarenes consisting of different phenolic units, having bridges other than methylene or showing inherent chirality (Cn-symmetry). Macrobi- and -tricyclic molecules such as bridged calixarenes, double calixarenes, bicyclocalixarenes and annelated calixarenes are also described. Single crystal X-ray structures are reported for several compounds. Some properties like conformational barriers, pKa values or the ability to complex metal ions are discussed, showing the potential of these compounds which may …
Convenient Synthesis of 3-Cinnamoyl-2-styrylchromones: Reinvestigation of the Baker-Venkataraman Rearrangement
2010
An efficient and straightforward, one-pot sequence gives access to highly functionalized 3-cinnamoyl-2-styrylchromones in excellent yields. The low solubility of the target molecules allows convenient isolation. The formation of an α,α-dicinnamoylated acetophenone, as a consequence of a two-fold Baker-Venkataraman sequence, has to be anticipated.
Racemattrennung, Kristallstruktur und histaminartige Wirkung von 4-[1-(2-Aminoethylthio)ethyl]-5-methylimidazol
1983
Es wird die Racemattrennung von 4-[1-(2-Aminoethylthio)ethyl]-5-methylimidazol (1) mittels optisch aktiver Di-O-(p-toluoyl)weinsaure sowie die histaminartige Wirksamkeit der Enantiomeren beschrieben. Von (+)-1 · 2HCl · H2O wurde die Kristallstruktur bestimmt und bis zu einem R-Wert von 0.0483 verfeinert. Danach ist (+)-1R-konfiguriert. Von den beiden Enantiomeren besitzt nur (S)-(−)-1 H1-agonistische Aktivitat. Resolution, Crystal Structure, and Histamine-like Activity of 4-[1-(2-Aminoethylthio)ethyl]-5-methylimidazole The resolution of racemic 4-[1-(2-aminoethylthio)ethyl]-5-methylimidazole (1) using optically active Di-O-(P-toluoyl)tartaric acid as well as the histamine-like activity of t…
Herstellung und eigenschaften von photometrisch quantitativ bestimmbaren, bei der polymerisation vernetzenden bisacrylsäureestern und von bispropions…
1969
Es wurden 6 Bisacrylsaureester hergestellt, die photometrisch quantitativ bestimmbare Strukturgruppen enthalten. Angaben zur Loslichkeit, IR-, UV-Absorptions- und 1H-NMR-Spektren dienten zur Charakterisierung der Verbindungen. Daneben wurden Dipropionsaureester synthetisiert, die sich durch Austausch der Acrylsaure- gegen die Propionsaurereste von den Bisacrylsaureestern ableiten. Verdunnte Losungen der Bisacrylsaure- und Dipropionsaureester folgen im Bereich von 250–450 mμ dem BOUGUER-LAMBERT-BEER-schen Gestz. Aus den Ergebnissen der Homopolymerisation der Bisacrylsaureester last sich schliesen, welche Ester fur eine einfache photometrische Analyse schwach vernetzter Copolymerer in Betrach…
N-(Diphenylmethylene)benzenesulfonamide andN-(Diphenylmethylene)-4-methylbenzenesulfonamide
2008
[10398-99-9] C19H15NO2S (MW 332.42) InChI = 1S/C19H15NO2S/c21-23(22,18-14-8-3-9-15-18)20-19(16-10-4-1-5-11-16)17-12-6-2-7-13-17/h1-15H InChIKey = LECLPBHPQOFADH-UHFFFAOYSA-N (reagent used as an activated imine) Physical Data: mp 119–120 °C. Form Supplied in: colorless crystals. Not commercially available. Purification: recrystalization from CH3OH. [10399-00-5] C20H17NO2S (MW 346.45) InChI = 1S/C20H17NO2S/c1-16-12-14-19(15-13-16)24(22,23)21-20(17-8-4-2-5-9-17)18-10-6-3-7-11-18/h2-15H,1H3 InChIKey = ODLFJRFKAOOIKO-UHFFFAOYSA-N (reagent used as an activated imine) Physical Data: mp 103–104 °C1; 102–103 °C2; 101–102 °C5; 103 °C6; 102–104 °C.7 Solubility: soluble in pyridine, dimethylformamide, …
Alkoxy-Substituted Hexastyrylbenzenes
2003
Star-shaped compounds 2a–e with a central benzene ring and six p-substituted, (E)-configured styryl groups have been prepared by a sequence of three-fold Heck and three-fold Wittig–Horner reactions. Alkoxy chains (OC3H7, OC6H13, OC10H21, OC12H25) on all six arms guarantee a good solubility of 2a–d, whereas the alternating hexyloxy and cyano substitution in 2e leads to an almost insoluble push-pull system. Irradiation into the long-wavelength absorption of 2a–d (with λmax values of 341–342 nm) results in a statistical photocross-linking, which is characterized by the complete degradation of all stilbene chromophores.
ChemInform Abstract: Two-Carbon Bridge Substituted Cocaines: Enantioselective Synthesis, Attribution of the Absolute Configuration, and Biological Ac…
2010
In an effort to learn more about the general structure-activity relationships of cocaine with the aim to elucidate those structural features that might confer antagonistic properties to such analogues, we describe herein our synthetic efforts to prepare two-carbon bridge functionalized (methoxylated and hydroxylated) analogues. Our approach makes use of a modification of the classical Willstatter synthesis of cocaine: Mannich type cyclization of acetonedicarboxylic acid monomethyl ester with methylamine hydrochloride and 2-methoxysuccindialdehyde in a citrate buffer solution afforded the 6- and 7-substituted 2-carbomethoxy-3-tropinones 3a,b and 4a,b in approximate yields of 64%. Reduction o…
Gekreuzt konjugierte oligomere aus pyrrol-, benzol- und carbonyl-Bausteinen
2004
Abstract Chalcones can serve as C 2 or C 3 components for the formation of 1 H -pyrroles. In particular the reaction with tosylisocyanid could be applied to the oligochalcones 2d - g with up to 6 enone units. A series of cross-conjugated oligomers 8d - g was obtained; these compounds consist of a chain of 1,4-phenylene, carbonyl and 1 H -pyrrole-3,4-diyl building blocks. The benzene rings bear two propoxy sidechains in order to enhance the solubility.
1984
By means of data from critical demixing and vapour pressure measurements and by inverse gas chromatography, including the results of published light scattering measurments, a consistent picture is obtained for the entire dependence of the Flory-Huggins parameter χ on the weight fraction w2 of the polymer and on the temperature T for the system tert-butyl acetate/polystyrene. Within the entire T-range (ca. 0°C – 140°C), χ increases stronger than exponentially with w2, the rise being the larger the larger χH (the enthalpy contribution to χ) becomes in the limit of infinite dilution. At sufficiently high temperatures (≳ 50°C), χH changes its sign from negative to positive as w2 is raised. This…
ChemInform Abstract: Giant Crown-Shaped Polytungstate Formed by Self-Assembly of CeIII-Stabilized Dilacunary Keggin Fragments.
2011
Single crystals of Na40K6[Ni(H2O)6]3 [K@K7Ce24Ge12W120O456 (OH)12(H2O)64]· 178H2O are synthesized by addition of KCl to a NaOAc/AcOH buffer solution containing Ce(NO3)3, GeO2, Na2WO4, and NiCl2 followed by slow evaporation at room temperature (24% yield).