|
| ||
|
|
||
Bicyclic Amines (bicyclic + amine)
Selected AbstractsBismuth-catalyzed cyclization of amino-1,6-enynesHETEROATOM CHEMISTRY, Issue 6 2008Kimihiro Komeyama Bi(OTf)3 effectively catalyzed the cyclization of amino-1,6-enynes, leading to bicyclic amine and cyclopentadienyl amino compounds. The selectivity of the products depends on the substitution pattern of the olefinic moiety. 19F NMR trace experiment of the reaction and other results indicate a novel alkynophilicity of the bismuth species. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:644,648, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20490 [source] Inhibition of pneumococcal choline-binding proteins and cell growth by esters of bicyclic aminesFEBS JOURNAL, Issue 2 2007Beatriz Maestro Streptococcus pneumoniae is one of the major pathogens worldwide. The use of currently available antibiotics to treat pneumococcal diseases is hampered by increasing resistance levels; also, capsular polysaccharide-based vaccination is of limited efficacy. Therefore, it is desirable to find targets for the development of new antimicrobial drugs specifically designed to fight pneumococcal infections. Choline-binding proteins are a family of polypeptides, found in all S. pneumoniae strains, that take part in important physiologic processes of this bacterium. Among them are several murein hydrolases whose enzymatic activity is usually inhibited by an excess of choline. Using a simple chromatographic procedure, we have identified several choline analogs able to strongly interact with the choline-binding module (C-LytA) of the major autolysin of S. pneumoniae. Two of these compounds (atropine and ipratropium) display a higher binding affinity to C-LytA than choline, and also increase the stability of the protein. CD and fluorescence spectroscopy analyses revealed that the conformational changes of C-LytA upon binding of these alkaloids are different to those induced by choline, suggesting a different mode of binding. In vitro inhibition assays of three pneumococcal, choline-dependent cell wall lytic enzymes also demonstrated a greater inhibitory efficiency of those molecules. Moreover, atropine and ipratropium strongly inhibited in vitro pneumococcal growth, altering cell morphology and reducing cell viability, a very different response than that observed upon addition of an excess of choline. These results may open up the possibility of the development of bicyclic amines as new antimicrobials for use against pneumococcal pathologies. [source] Photocycloaddition of Six-Membered Cyclic Enones to Propen-2-yl IsocyanateHELVETICA CHIMICA ACTA, Issue 8 2007Maryam Bahaji Abstract On irradiation in the presence of propen-2-yl isocyanate (4), six-membered cyclic enones 3 are converted into regio- and stereoisomeric mixtures of [2+2] cycloadducts 5,10; the preferentially formed HT products, 5,8, can be converted into the corresponding bicyclic amines by acid hydrolysis, whereas, under these conditions, the regioisomeric HH -isocyanato derivatives undergo a retro-Mannich reaction. [source] | ||||||||||