UV absorption and keto–enol tautomerism equilibrium of methoxy and dimethoxy 1,3-diphenylpropane-1,3-diones
作者:Jan Zawadiak、Marek Mrzyczek
DOI:10.1016/j.saa.2009.12.040
日期:2010.2
dimethoxy derivatives (5-10) in various solvents dissolved were collected. The keto-enol tautomerism equilibrium constant was calculated with (1)H NMR. The position of the methoxy group in 1,3-diphenylpropane-1,3-dione was shown to have an influence on the molecule's UV absorption spectrum and the keto-enol tautomerism equilibrium constant. The methoxy group in the para position increases the absorption
收集1,3-二苯基丙烷-1,3-二酮(1),其三种甲氧基衍生物(2-4)和其六种二甲氧基衍生物(5-10)在各种溶解溶剂中的紫外吸收光谱。酮-烯醇互变异构平衡常数通过(1)1 H NMR计算。1,3-二苯丙烷-1,3-二酮中甲氧基的位置显示出对分子的紫外线吸收光谱和酮-烯醇互变异构平衡常数的影响。对位的甲氧基增加了UV-A范围内辐射的吸收。在邻位具有甲氧基的化合物经历在酮-烯醇互变异构平衡中向酮形式的转变。当存在两个甲氧基时,它们位置的影响是累积的。
Chemo‐ and Regioselective Construction of Functionalized Isocoumarin, Flavone, and Isoquinolinedione
<i>via</i>
a One‐pot Reaction of
<i>o</i>
‐Quinol Acetate and Soft Nucleophiles
strategy for the synthesis of substituted isocoumarin, flavone, and isoquinolinedione derivatives through a switchable C-arylation/lactonization or SNAr reaction from a wide range of soft nucleophiles and o-quinol acetates has been developed. This base-mediated protocol proceeds under transition-metal-free conditions and selectively affords various heteroarenes in 13–98% yields from readily prepared or commercially
已经开发出一种通过可切换的 C-芳基化/内酯化或 SNA Ar 反应从各种软亲核试剂和邻羟基乙酸酯合成取代异香豆素、黄酮和异喹啉二酮衍生物的一锅策略。这种碱介导的方案在无过渡金属的条件下进行,并从易于制备或市售的 1,3-二羰基和α -EWG 取代的羰基化合物中选择性地以 13-98% 的产率提供各种杂芳烃。该合成效用在潜在抗HIV 和抗 HIV 药物的合成中得到了进一步证明。-冠状病毒衍生物和COX-2抑制剂。此外,还进行了详细的实验和计算研究,以提供对反应机理的深入理解和有力支持。
Co‐Catalyzed Dehydrogenation Claisen Condensation of Secondary Alcohols with Esters†
practical Co-catalyzed cascade dehydrogenative Claisen condensation of secondaryalcohols with esters, facilitating the synthesis of a wide range of 3-hydroxy-prop-2-en-1-ones. We introduce a catalytic system based on novel and scalable indazole NNP-ligands coordinated to cobalt for efficient dehydrogenations of secondaryalcohols, and propose a plausible reaction mechanism supported by control experiments