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Dibromo Derivative (dibromo + derivative)

Distribution by Scientific Domains

Chemistry	80%

Selected Abstracts

Reaction of 1,2-Diamino-4,5-diphenylimidazole with 1,3-Diarylpropenones and Their Dibromo Derivatives.

CHEMINFORM, Issue 15 2004
N. N. Kolos
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Synthesis of "V-Shaped" syn -Bidentate Ligands Based on Mesitylene-Derived [1.1.1.1]Metacyclophane Blocked in a 1,3-Alternate Conformation

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 2 2003
Cédric Klein
Abstract A series of five new syn -bidentate ligands 14,18 based on the [1.1.1.1]metacyclophane backbone blocked in a 1,3-alternate conformation was achieved. The common building block for the preparation of ligands bearing two interaction sites located in a syn fashion (CN, SMe, p -pyridyl, p -methoxyphenyl and p -methylthiophenyl) is the dibromo derivative 12. All reported ligands were fully characterised by classical analytical methods and their 1,3-alternate conformation demonstrated. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source]

Rosiglitazone maleate (BRL 49653-C); the preparation of [14C] and [3H] isotopomers

JOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 5 2001
Tabassum Kirefu
Abstract The glitazone insulin sensitisers are an important class of pharmaceuticals for the treatment of Type 2 diabetes. Syntheses of [methyl - 14C] and [3H]rosiglitazone maleate (BRL 49653-C), marketed by SmithKline Beecham Pharmaceuticals as Avandia® are described. [Methyl - 14C]BRL 49653-C was prepared in 5 steps in 12.6% overall radiochemical yield from K[14C]CN. Catalytic reduction with tritium gas of a dibromo derivative gave [3H]rosiglitazone with a specific activity of 58Ci/mmol. Copyright © 2001 John Wiley & Sons, Ltd. [source]

A Self-Assembling Polythiophene Functionalised with a Cysteine Moiety

MACROMOLECULAR RAPID COMMUNICATIONS, Issue 9 2003
Adele Mucci
Abstract A new copolymer bearing a cysteine moiety, designed for molecular interaction, metal-ion detection, and chiral recognition, was synthesised starting from the dibromo derivative of methyl N -(tert -butoxycarbonyl)- S -thien-3-ylcysteinate and distannylthiophene through a Stille coupling reaction. UV-vis spectroscopy, circular dichroism, NMR spectroscopy, and gel permeation chromatography analyses evidenced that this polymer is able to form self-assembling structures, through the formation of a hydrogen-bond network, not only in the solid state but also in solution. [source]

Experimental and predicted crystal structures of Pigment Red 168 and other dihalogenated anthanthrones

ACTA CRYSTALLOGRAPHICA SECTION B, Issue 5 2010
Martin U. Schmidt
The crystal structures of 4,10-dibromo-anthanthrone (Pigment Red 168; 4,10-dibromo-dibenzo[def,mno]chrysene-6,12-dione), 4,10-dichloro- and 4,10-diiodo-anthanthrone have been determined by single-crystal X-ray analyses. The dibromo and diiodo derivatives crystallize in P21/c, Z = 2, the dichloro derivative in , Z = 1. The molecular structures are almost identical and the unit-cell parameters show some similarities for all three compounds, but the crystal structures are neither isotypic to another nor to the unsubstituted anthanthrone, which crystallizes in P21/c, Z = 8. In order to explain why the four anthanthrone derivatives have four different crystal structures, lattice-energy minimizations were performed using anisotropic atom,atom model potentials as well as using the semi-classical density sums (SCDS-Pixel) approach. The calculations showed the crystal structures of the dichloro and the diiodo derivatives to be the most stable ones for the corresponding compound; whereas for dibromo-anthanthrone the calculations suggest that the dichloro and diiodo structure types should be more stable than the experimentally observed structure. An experimental search for new polymorphs of dibromo-anthanthrone was carried out, but the experiments were hampered by the remarkable insolubility of the compound. A metastable nanocrystalline second polymorph of the dibromo derivative does exist, but it is not isostructural to the dichloro or diiodo compound. In order to determine the crystal structure of this phase, crystal structure predictions were performed in various space groups, using anisotropic atom,atom potentials. For all low-energy structures, X-ray powder patterns were calculated and compared with the experimental diagram, which consisted of a few broad lines only. It turned out that the crystallinity of this phase was not sufficient to determine which of the calculated structures corresponds to the actual structure of this nanocrystalline polymorph. [source]