19728-23-5Relevant articles and documents
Catalyst-free photoredox addition-cyclisations: Exploitation of natural synergy between aryl acetic acids and maleimide
Manley, David W.,Mills, Andrew,O'Rourke, Christopher,Slawin, Alexandra M. Z.,Walton, John C.
supporting information, p. 5492 - 5500 (2014/05/20)
Suitably functionalised carboxylic acids undergo a previously unknown photoredox reaction when irradiated with UVA in the presence of maleimide. Maleimide was found to synergistically act as a radical generating photoxidant and as a radical acceptor, negating the need for an extrinsic photoredox catalyst. Modest to excellent yields of the product chromenopyrroledione, thiochromenopyrroledione and pyrroloquinolinedione derivatives were obtained in thirteen preparative photolyses. In situ NMR spectroscopy was used to study each reaction. Reactant decay and product build-up were monitored, enabling reaction profiles to be plotted. A plausible mechanism, whereby photo-excited maleimide acts as an oxidant to generate a radical ion pair, has been postulated and is supported by UV/Vis. spectroscopy and DFT computations. The radical-cation reactive intermediates were also characterised in solution by EPR spectroscopy. UVA photolyses of aryloxy-, arylthio- and arylamino-acetic acids with maleimide yield oxa-, thia- and aza-tricyclo pyrroledione derivatives in the absence of a photoredox catalyst (see scheme). An intriguing mechanism has been proposed and has been supported and supplemented by NMR monitoring experiments, DFT computations and UV/Vis and EPR spectroscopy.
Dimethoxyaurones: Potent inhibitors of ABCG2 (breast cancer resistance protein)
Sim, Hong-May,Lee, Chong-Yew,Ee, Pui Lai Rachel,Go, Mei-Lin
, p. 293 - 306 (2008/12/23)
A series of 4,6-dimethoxyaurones were synthesized by reacting 4,6-dimethoxybenzofuran-3(2H)-one with various benzaldehydes in a base-catalyzed aldol reaction. A Z configuration was assigned to the aurones based on spectroscopic and crystallographic data.
Novel benzo[1,4]diazepin-2-one derivatives as endothelin receptor antagonists
Bolli, Martin H.,Marfurt, Judith,Grisostomi, Corinna,Boss, Christoph,Binkert, Christoph,Hess, Patrick,Treiber, Alexander,Thorin, Eric,Morrison, Keith,Buchmann, Stephan,Bur, Daniel,Ramuz, Henri,Clozel, Martine,Fischli, Walter,Weller, Thomas
, p. 2776 - 2795 (2007/10/03)
Since its discovery in 1988 by Yanagisawa et al., endothelin (ET), a potent vasoconstrictor, has been widely implicated in the pathophysiology of cardiovascular, cerebrovascular, and renal diseases. Many research groups have embarked on the discovery and development of ET receptor antagonists for the treatment of such diseases. While several compounds, e.g., ambrisentan 2, are in late clinical trials for various indications, one compound (bosentan, Tracleer) is being marketed to treat pulmonary arterial hypertension. Inspired by the structure of ambrisentan 2, we designed a novel class of ET receptor antagonists based on a 1,3,4,5-tetrahydro-1H-benzo[e][1,4]diazepin-2-one scaffold. Here, we report on the preparation as well as the in vitro and in vivo structure-activity relationships of these derivatives. Potent dual ET A/ETB receptor antagonists with affinities in the low nanomolar range have been identified. In addition, several compounds efficiently reduced arterial blood pressure after oral administration to Dahl salt sensitive rats. In this animal model, the efficacy of the benzo[e] [1,4]diazepin-2-one derivative rac-39au was superior to that of racemic ambrisentan, rac-2.
