7298-72-8Relevant academic research and scientific papers
Prenylcoumarins in One or Two Steps by a Microwave-Promoted Tandem Claisen Rearrangement/Wittig Olefination/Cyclization Sequence
Schultze, Christiane,Schmidt, Bernd
, p. 5210 - 5224 (2018/05/17)
The one-pot synthesis of 8-prenylcoumarins from 1,1-dimethylallylated salicylaldehydes and the stabilized ylide [(ethoxycarbonyl)methylene]triphenylphosphorane under microwave conditions was found to have a limited scope. The sequence suffers from a difficult and sometimes low-yielding synthesis of the precursors and from a competing deprenylation upon microwave irradiation. This side reaction occurs in particular with electron rich arenes with two or more alkoxy groups at adjacent positions, a prominent substitution pattern in naturally occurring 8-prenylcoumarins. Both limitations of this one-step sequence were overcome by a two-step synthesis consisting of a microwave-promoted tandem allyl ether Claisen rearrangement/Wittig olefination and a subsequent olefin cross metathesis with 2-methyl-2-butene. The cross metathesis step proceeds with a high selectivity and yields exclusively the desired prenyl, rather than the alternative crotyl substituent. Several naturally occurring 8-prenylcoumarins that were previously inaccessible have been synthesized in good overall yields along this route.
Pharmaceutical compositions having β-adrenoceptor antagonist activity employing pyridazinone derivatives
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, (2008/06/13)
This invention relates to (isopropyl and tertiary butyl-amino-2-hydroxypropoxy)phenyl-3[2H]-pyridazinones which have β-adrenoceptor antagonist activity.
New Antiallergic Pyranoquinoline-2,8-dicarboxylic Acids with Potential for the Topical Treatment of Asthma
Cairns, Hugh,Cox, David,Gould, Ken J.,Ingall, Anthony H.,Suschitzky, John L.
, p. 1832 - 1842 (2007/10/02)
A nimber of antiallergic pyranoquinolinedicarboxylic acid derivatives with potential for the topical treatment of asthma have been synthesized.All the compounds have been evaluated against rat passive cutaneous anaphylaxis and in a dog hypotension screen.This is the first detailed description of the application of the latter screen for the identification of antiallergic agents.Two compounds, disodium 9-ethyl-6,9-dihydro-4,6-dioxo-10-propyl-4H-pyranoquinoline-2,8-dicarboxylate (86) and disodium 6-(methylamino)-4-oxo-10-propyl-4H-pyranoquinoline-2,8-dicarboxylate (72), were selected and further evaluated for their ability to induce phosphorylation of a 78000 molecular weight protein associated with the rat peritoneal mast cell.Their ability to inhibit histamine release from these cells and from a mucosal mast cell preparation has also been evaluated.These compounds, nedocromil sodium (TILADE 86) and minocromil (the free acid of 72), are at present undergoing therapeutic evaluation.The rationale for the screening procedure and the relevance of the second carboxylic acid function of these dibasic acids to receptor binding are discussed.
7,6 Dioxo-4H,6H-pyrano[3,2-g]quinoline dicarboxylic acids and anti-allergic use thereof
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, (2008/06/13)
There are described compounds of formula I STR1 in which an adjacent pair of R5, R6, R7 and R8 form a chain --COCH=CE--O--, and the remainder of R5, R6, R7 and R8, whi
