A Formal [3 + 3] Cycloaddition Reaction. Improved Reactivity Using α,β-Unsaturated Iminium Salts and Evidence for Reversibility of 6π-Electron Electrocyclic Ring Closure of 1-Oxatrienes
摘要:
A detailed account regarding a formal [3 + 3] cycloaddition method using 4-hydroxy-2-pyrones and 1,3-diketones is described here. This formal cycloaddition reaction or annulation reaction is synthetically useful for constructing 2H-pyranyl heterocycles. The usage of alpha,beta-unsaturated iminium salts is significant in controlling competing reaction pathways to give exclusively 2H-pyrans. Most significantly, experimental evidence is provided to support the mechanism of this reaction that involves a sequential Knoevenagel condensation and a reversible 6pi-electron electrocyclic ringclosure of 1-oxatrienes.
Synthesis and UV Studies of A Small Library of 6-Aryl-4-hydroxy-2-pyrones. A Relevant Structural Feature for the Inhibitory Property of Arisugacin Against Acetylcholinesterase
摘要:
4-Hydroxypyrones belong to an important class of compounds not only because of their medicinal significance, but also because they represent a common structural feature among natural products that ale biologically relevant. We describe here preparations of a small library of 6-aryl-4-hydroxy-pyrones which represent structural analogs of the DE-ring of arisugacin, a potent and selective inhibitor against acetylcholinesterase. Given the structural significance of the DE-ring in the inhibitory activity of arisugacin, chemical shifts of relevant protons on the pyrone ring are compared, and distinct features in UV absorptions of these 6-aryl-4-hydroxy-pyrones are described. (C) 1999 Elsevier Science Ltd. All rights reserved.
Synthesis and antimicrobial activity of new prenylated 2-pyrone derivatives
作者:Grace Obi、Jude C. Chukwujekwu、Fanie R. van Heerden
DOI:10.1080/00397911.2020.1718710
日期:2020.3.3
Abstract A series of new monoprenylated and diprenylated 2-pyrone derivatives with different halogen substituents were synthesized from the corresponding 6-aryl-4-hydroxy-2-pyrones by prenylation reactions. The compounds were evaluated for antibacterial activity and displayed significant in vitro activity with the highest activity shown by the monoprenylated 6-aryl-2-pyrones. All the compounds except
摘要 以相应的6-芳基-4-羟基-2-吡喃酮为原料,通过异戊二烯化反应合成了一系列具有不同卤素取代基的单异戊二烯化和二异戊二烯化2-吡喃酮衍生物。对化合物的抗菌活性进行了评估,并显示出显着的体外活性,其中单异戊二烯化 6-芳基-2-吡喃酮的活性最高。除含溴类似物外,所有化合物均对一种或多种测试细菌具有活性,其中大肠杆菌是最敏感的测试生物。由于其中八种化合物对产生耐药性 β-内酰胺酶的肺炎克雷伯菌具有显着的抗菌活性,因此对这些化合物中的每一种与氨苄青霉素之间的协同作用进行了评估。在研究的八种组合中,观察到两种化合物的协同作用,4-(3-methylbut-2-enoxy)-6-phenyl-2H-pyran-2-one 和 6-(4-fluorophenyl)-4-(3-methylbut-2-enoxy) )-2H-吡喃-2-一。两种化合物,在单个 MIC 值的一半时,都能够将氨苄青霉素组合的
A Formal [3 + 3] Cycloaddition Reaction. Improved Reactivity Using α,β-Unsaturated Iminium Salts and Evidence for Reversibility of 6π-Electron Electrocyclic Ring Closure of 1-Oxatrienes
作者:Hong C. Shen、Jiashi Wang、Kevin P. Cole、Michael J. McLaughlin、Christopher D. Morgan、Christopher J. Douglas、Richard P. Hsung、Heather A. Coverdale、Aleksey I. Gerasyuto、Juliet M. Hahn、Jia Liu、Heather M. Sklenicka、Lin-Li Wei、Luke R. Zehnder、Craig A. Zificsak
DOI:10.1021/jo020688t
日期:2003.3.1
A detailed account regarding a formal [3 + 3] cycloaddition method using 4-hydroxy-2-pyrones and 1,3-diketones is described here. This formal cycloaddition reaction or annulation reaction is synthetically useful for constructing 2H-pyranyl heterocycles. The usage of alpha,beta-unsaturated iminium salts is significant in controlling competing reaction pathways to give exclusively 2H-pyrans. Most significantly, experimental evidence is provided to support the mechanism of this reaction that involves a sequential Knoevenagel condensation and a reversible 6pi-electron electrocyclic ringclosure of 1-oxatrienes.
Synthesis and UV Studies of A Small Library of 6-Aryl-4-hydroxy-2-pyrones. A Relevant Structural Feature for the Inhibitory Property of Arisugacin Against Acetylcholinesterase
作者:Christopher J. Douglas、Heather M. Sklenicka、Hong C. Shen、David S. Mathias、Shane J. Degen、Geoffrey M. Golding、Christopher D. Morgan、Regina A. Shih、Kristen L. Mueller、Lisa M. Scurer、Erik W. Johnson、Richard P. Hsung
DOI:10.1016/s0040-4020(99)00847-9
日期:1999.11
4-Hydroxypyrones belong to an important class of compounds not only because of their medicinal significance, but also because they represent a common structural feature among natural products that ale biologically relevant. We describe here preparations of a small library of 6-aryl-4-hydroxy-pyrones which represent structural analogs of the DE-ring of arisugacin, a potent and selective inhibitor against acetylcholinesterase. Given the structural significance of the DE-ring in the inhibitory activity of arisugacin, chemical shifts of relevant protons on the pyrone ring are compared, and distinct features in UV absorptions of these 6-aryl-4-hydroxy-pyrones are described. (C) 1999 Elsevier Science Ltd. All rights reserved.