Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Une premiere partie de cette these decrit une approche synthetique vers la celogentine C, molecule naturelle extraite de graines de Celosia argentea, qui presente des proprietes antimitotiques interessantes par inhibition de la polymerisation de la tubuline. La presence de liaisons inhabituelles au sein de ce compose (entre les chaines laterales d'une leucine, d'un tryptophane et d'une histidine) procure a cet octapeptide bicyclique une structure originale. Le fragment beta-leucine-trytophane de la celogentine C a pu etre prepare de maniere controlee par une reaction d'hydrogenation asymetrique. Une deuxieme partie concerne le developpement de reactions catalysees par le chlorure de fer(III). L'hydroamination de styrenes par differents nucleophiles azotes desactives et la cyclisation de 2-alkynylanilines non-protegees en indoles (dans ce cas, en association avec le palladium) ont pu etre catalysees par ce complexe de fer. Le caractere acide de Lewis du fer a egalement ete mis a profit pour la synthese one-pot de bis(indolyl)methanes.
Abstract Direct functionalization of protected histidines with arylboronic acids is described under Chan–Lam–Evans conditions to give the corresponding N (τ)‐arylhistidines in moderate to good yields (12 examples, up to 83 % yield) under mild conditions.
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Protease activated receptors (PARs) or thrombin receptors constitute a class of G-protein-coupled receptors (GPCRs) implicated in the activation of many physiological mechanisms. Thus, thrombin activates many cell types such as vascular smooth muscle cells, leukocytes, endothelial cells, and platelets via activation of these receptors. In humans, thrombin-induced platelet aggregation is mediated by one subtype of these receptors, termed PAR1. This article describes the discovery of new antagonists of these receptors and more specifically two compounds: 2-[5-oxo-5-(4-pyridin-2-ylpiperazin-1-yl)penta-1,3-dienyl]benzonitrile 36 (F 16618) and 3-(2-chlorophenyl)-1-[4-(4-fluorobenzyl)piperazin-1-yl]propenone 39 (F 16357), obtained after optimization. Both compounds are able to inhibit SFLLR-induced human platelet aggregation and display antithrombotic activity in an arteriovenous shunt model in the rat after iv or oral administration. Furthermore, these compounds are devoid of bleeding side effects often observed with other types of antiplatelet drugs, which constitutes a promising advantage for this new class of antithrombotic agents.
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Owing to their significant abundance in natural products, chiral β,β′-disubstituted α-amino acids remain an important synthetic objective. Emphasis has been focused in this critical review on the great diversity of enantio- and diastereoselective methodologies to reach these highly functionalized compounds. The oldest and cutting edge synthetic methods are described in parallel with the synthesis of many relevant biologically active targets (224 references).
