Direct synthesis of 3,5‐diaryl‐1,2,
<scp>4‐oxadiazoles</scp>
using 1‐(2‐oxo‐2‐arylethyl)pyridin‐1‐iums with benzamidines
作者:Yue Zhang、Chengjun Wu、Xinyi Wan、Cunde Wang
DOI:10.1002/jhet.4354
日期:2021.12
An efficient domino protocol for the synthesis of 1,2,4-oxadiazole derivatives from readily available 1-(2-oxo-2-arylethyl)pyridin-1-iums and amidine hydrochlorides was developed. In this practical approach, N-acyl amidine precursors were formed firstly via a simple nucleophilic substitution, without the purification of N-acylamidine intermediates, and the following intramolecularly dehydrative cyclization
开发了一种用于从容易获得的 1-(2-oxo-2-arylethyl)pyridin-1-iums 和脒盐酸盐合成 1,2,4-恶二唑衍生物的有效多米诺协议。在该实用的方法,Ñ酰基脒前体通过简单的亲核取代首先形成,未经纯化Ñ -acylamidine中间体和分子内下列脱水闭环中的我的存在下,得到1,2,4-恶二唑衍生物2 / K 2 CO 3 /DMSO 表现出优异的官能团耐受性并在简单的实验条件下进行。
N-Heterocyclic Carbene Catalyzed Intramolecular Hydroacylation of Alkynylphosphonates
作者:Deqing Shi、Zhenqiang Wang、Zhihua Yu、Ying Wang
DOI:10.1055/s-0031-1290976
日期:2012.5
applied in the one-pot synthesis of benzopyranopyridine phosphonates in moderated yields. Two exocyclic and endocyclic olefin tautomers of chromone phosphonates were obtained in good to excellent yields at different temperatures by utilizing an N-heterocyclic carbene catalyst in the intramolecular reactions between the formyl group and alkynylphosphonates. The exocyclicolefins can isomerize to the endocyclic
Cyclization of Active Methylene Isocyanides with α-Oxodithioesters Induced by Base: An Expedient Synthesis of 4-Methylthio/Ethoxycarbonyl-5-acylthiazoles
作者:Toreshettahally R. Swaroop、Kanchugarakoppal S. Rangappa、Maralinganadoddi P. Sadashiva、Kuppalli R. Kiran、Narasimhamurthy Rajeev、Seegehalli M. Anil
DOI:10.1055/s-0039-1690821
日期:2020.5
Cyclization of tosylmethylisocyanide with α-oxodithioesters in the presence of KOH is reported for the synthesis of 4-methylthio-5-acylthiazoles. Similarly, ethyl isocyanoacetate underwent cyclization with α-oxodithioesters to form 4-ethoxycarbonyl-5-acylthiazoles in the presence of DBU/EtOH. Mechanisms for the formation of thiazoles are proposed. These thiazoles can also be obtained by Takeda reaction
acid (TFA)-mediated cascadeoxidation/1,3-dipolarcycloaddition reaction of stabilized pyridinium salts with dimethyl sulfoxide (DMSO) has been developed in the presence of K2S2O8 and trimethylethylenediamine (TMEDA). In this transition-metal-free reaction, DMSO acts as a one-carbon source, thus providing a convenient method for the efficient and direct synthesis of various indolizine derivatives.
Iodine-promoted synthesis of acylindolizine derivatives from acetylenecarboxylates and pyridinium, isoquinolinium, or quinolinium ylides
作者:Juanjuan Liu、Peiyun Yan、Yan Li、Zhengquan Zhou、Weijian Ye、Juan Yao、Cunde Wang
DOI:10.1007/s00706-013-1120-6
日期:2014.4
AbstractAn iodine-promoted synthesis of acylindolizinecarboxylates via 1,3-dipolar cycloaddition of nitrogen ylides with acetylenecarboxylates and subsequent aromatization for the generation of a wide range of structurally interesting, pharmacologically and photoelectrically significant compounds is reported. Only readily available materials, mild conditions, and operationally trivial reaction protocols