The Synthesis of Phosphaisocoumarins by Cu(I)-Catalyzed Intramolecular Cyclization of <i>o</i>-Ethynylphenylphosphonic Acid Monoesters
作者:Ai-Yun Peng、Yi-Xiang Ding
DOI:10.1021/ja038627f
日期:2003.12.1
Cu(I)-catalyzed intramolecular cyclization of o-ethynylphenylphosphonic acid monoethyl esters was examined, and a new class of six-membered phosphorus heterocycles was formed with high regioselectivity and good yields. The present reaction is the first example of intramolecular addition of P-OH to alkynes, which provides a convenient way to synthesize novel phosphorus heterocycles having potential
In this work, we found that acids (i.e., HCl and NaHSO3) rather than bases could catalyze the cyclization of o-alkynylphenylphosphonicacidmonoesters at slow rates and give phosphaisocoumarins in low to medium yields, whereas the cyclization of (o-hydroxyphenyl)ethynylphosphinates proceeded very smoothly under basic conditions rather than acidic conditions, and a series of phosphachromones could be
Synthesis of phosphaisocoumarin amidates via DIBAL-H-mediated selective amidation of phosphaisocoumarin esters
作者:Yu-Juan Guo、Pei-Jiang Chen、Bo Wang、Ai-Yun Peng
DOI:10.1039/c4ob00663a
日期:——
A series of phosphaisocoumarin amidates were synthesized via DIBAL-H-mediated selective amidation of phosphaisocoumarin esters in good to excellent yields. In each case, the phostone ring was intact and only the exocyclic ethoxy group was amidated.
4-bromophosphaisocoumarins underwent a dehalogenation–alcoholysis tandem reaction. The possible mechanism for the alcoholysis reaction was discussed. In addition, direct access to 2-(2-oxoalkyl)phenylphosphonates was developed by the mercury(II)-catalyzed hydration of 2-(1-alkynly)phenylphosphonates with high regioselectivity. In a preliminary study, the obtained novel keto phosphonates showed medium inhibitory
Due to the importance of pancreatic cholesterol esterase (CEase) as a potential target in atherosclerosis and for the development of hypocholesterolemic agents, there are increasing interests in designing and synthesizing CEase inhibitors. In the present study, we prepared forty-five isocoumarin phosphorus analogues (i.e., phosphaisocoumarins) and investigated the inhibition of these compounds on the CEase. The results showed that some phosphaisocoumarins could act as potent inhibitors of CEase. The most potent inhibitors, compounds 9d, 10a and 12e give IC(50) values of 4.8 mu M, 2.3 mu M and 1.9 mu M, respectively. The inhibition mechanism and kinetic characterization studies indicate that they are reversible competitive inhibitors. (C) 2010 Published by Elsevier Masson SAS.