Search results for "medicinal"

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.

An unsolvated erbium organyl: (2,4,6,2′′,4′′,6′′-hexamethyl-1,1′:3′;1′′-terphenyl-2′-yl)bis(methylcyclopentadienyl)erbium(III)

2007

The title compound, [Er(Dmp)(C5H4Me)2] (Dmp = 2,6-Mes2C6H3, with Mes = 2,4,6-Me3C6H2) or [Er(C6H7)2(C24H25)], was obtained by the reaction of LiDmp with Er(C5H4Me)3. The Er atom is η5-coordinated by two methyl­cyclo­penta­dienyl ligands (average Er⋯centroid distance = 2.341 A) and η1-coordinated by the ipso-C atom of the aryl substituent [Er—C = 2.434 (4) A]. An additional π-arene contact with one of the Mes groups [Er⋯C = 3.077 (4) A] gives rise to the pyramidalization of the metal-atom environment.

Mononuclear heterocyclic rearrangement. Part 6 . Studies on base catalysis of the rearrangement of the (Z)-p-nitrophenylhydrazone of 3-benzoyl-5-phen…

1981

Triazolopyridines. Part 26: The preparation of novel [1,2,3]triazolo[1,5-a]pyridine sulfoxides

2008

Abstract The regioselective synthesis of new triazolopyridine halides and sulfoxides with the substituent in all different ring positions of [1,2,3]triazolo[1,5- a ]pyridines is presented. The triazolo ring opening reaction of some representative sulfoxides to obtain disubstituted pyridines is also studied.

The reaction of amino-imidazoles, -pyrazoles and -triazoles with α,β-unsaturated nitriles

2005

The reactions of α,β-unsaturated nitriles (1, 9, 12) as bielectrophiles with aminoazoles (2, 4, 6) as binu-cleophiles were investigated. Acrylonitrile (1) reacts almost exclusively in a chemoselective Michael-type addition yielding the substituted azoles 3, 5 and 7, respectively. Cinnamonitriles 9a,b behave in a similar way, but the free CN group adds a second molecule 4 yielding 10a,b and its cyclocondensation product 11a,b as minor component. The attempted formation of azolopyrimidines is best achieved by the reaction of the benzylidenemalononitriles 12a - f with 2 or 4. The process is chemo- and regioselective. The structure determinations were based on NMR measurements including DEFT, C…

The Introduction of Substituents into the Pyridine Ring

1964

catena-Poly[benzyltriethylammonium [tri-μ-thiocyanato-κ4N:S;κ2S:N-cadmate(II)]]

2006

The title compound, {[(C6H5CH2)N(C2H5)3][Cd(SCN)3]}n, contains benzyl­triethyl­ammonium cations lying between one-dimensional chains of stoichiometry {[Cd(SCN)3]−}n. Each Cd2+ ion is 3N,3S-hexa­coordinated by thio­cyanate ligands in an octa­hedral arrangement. The asymmetric unit contains one cation and one anion.

ChemInform Abstract: Reversal of Asymmetric Induction in Stereoselective Strecker Synthesis on Galactosyl Amine as the Chiral Matrix.

1989

Abstract The reversal of the direction of asymmetric induction in Lewis acid catalyzed Strecker synthesis using the 2,3,4,6-tetra-O-pivaloyl-β-D-galactopyranosyl amine 1 is described. In isopropanol or tetrahydrofuran 1 had given ( R )-diastereomers of the corresponding α-amino nitriles preferably. However, in chloroform in the presence of heterogeneous zinc chloride the same auxiliary alternatively leads to an excess of the ( S )-diastereomers.

ChemInform Abstract: Influence of Reactant Polarity on the Course of the Inverse-Electron-Demand Diels-Alder Reaction. A DFT Study of Regio- and Ster…

2010

The molecular mechanisms for the inverse-electron-demand Diels−Alder reactions between nitroethene and three substituted ethenes (propene, methyl vinyl ether, and dimethylvinylamine) to give the corresponding nitroso cycloadducts have been characterized with density functional theory methods using the B3LYP/6-31G* calculational level. On the basis of stability arguments and molecular orbital analysis relative rates, regioselectivity, and stereoselectivity, the presence of Lewis acid catalyst modeled by the BH3 system and the inclusion of solvent effects as a function of the nature of substituent in the dienophile fragment are analyzed and discussed. The ortho attack mode presents transition…

N-Bromosuccinimide, Its Properties and Reactions The Course of Substitution

1964