Three-Component Condensation of Pyridinium Ylides, β-Ketonitriles, and Aldehydes with Divergent Regioselectivity: Synthesis of 4,5-Dihydrofuran-3- and 2<i>H</i>-Pyran-5-carbonitriles
作者:Maxim R. Demidov、Vitaly A. Osyanin、Dmitry V. Osipov、Yuri N. Klimochkin
DOI:10.1021/acs.joc.1c00423
日期:2021.6.4
and semistabilized pyridinium ylide precursors, and aldehydes in the presence of piperidine. This one-pot transformation generates two C–C and one C–O bond and proceeds through a cascade Knoevenagel condensation, a Michael addition, and intramolecular SN2 cyclization. Formation of cyclopropanecarbonitrile derivatives, which in some cases were obtained as major products, was found to be a competing
通过β-酮腈、羰基和半稳定化的吡啶鎓叶立德前体以及醛在哌啶存在下的三组分反应,以非对映选择性方式合成了反式-4,5-二氢呋喃-3-甲腈文库。这种一锅转化生成两个C-C和一个C-O键并经由级联Knoevenagel缩合,迈克尔加成,和分子内小号Ñ 2环化。发现在某些情况下作为主要产物获得的环丙烷甲腈衍生物的形成是一种竞争反应。芳基乙二醛的使用会改变区域选择性并产生 2-hydroxy-2 H - pyran -5-carbonitriles。
Non-thermal internal energy distribution of ions observed in an electrospray source interfaced with a sector mass spectrometer
The internalenergy distribution P(Eint) of ions emitted in an electrospray (ESI) source interfaced with a sector massspectrometer is evaluated by using the experimental survival yield (SY) method including the kinetic shift. This method is based on the relationship between the degree of fragmentation of an ion and its amount of internalenergy and uses benzylpyridinium cations due to their simple
An ion-pair compound based on [Pd(mnt)2]− with strong antiferromagnetically coupled interaction: synthesis, crystal structure, magnetic property
作者:X.M. Ren、H. Okudera、J.L. Xie、Q.J. Meng
DOI:10.1016/j.molstruc.2004.08.009
日期:2005.1
interactions were observed between adjacent benzene rings within a cationic column. The temperature dependence of magnetic susceptibility measured in the temperature range of 1.8–330 K; indicates this compound is almost diamagnetic. The magnetic susceptibility was successfully modeled by a spin dimer magnetic exchange scheme with s = 1 2 to give rise to g =2.1, and the energy gap between singlet ground state and
Copper-Catalyzed Oxidative [3 + 2] Cycloaddition of <i>N</i>-Alkyl Pyridinium Salts to Imidazo[1,2-<i>a</i>]pyridines
作者:Yuan Zhang、Weibin Fan、Yinghua Li、Deguang Huang
DOI:10.1021/acs.joc.3c00728
日期:2023.9.1
A copper-catalyzed reaction of pyridiniumsalts and trimethylsilyl cyanide (TMSCN) in the presence of diethyl phosphite is developed. This reaction, which allows the single-step construction of biologically important 2-cyanoimidazo[1,2-a]pyridine from readily available starting materials, is realized for the first time and is feasible at the gram scale. The scope of the protocol is demonstrated with
开发了在亚磷酸二乙酯存在下吡啶鎓盐和三甲基硅烷基氰化物 (TMSCN) 的铜催化反应。该反应首次实现了从容易获得的起始材料一步构建生物学上重要的2-氰基咪唑并[1,2- a ]吡啶的反应,并且在克级是可行的。该协议的范围通过 27 个示例进行了演示。在这一一锅法中可以实现连续的双氰化和环化。TMSCN 发挥双重作用,不仅作为“CN”源,而且作为咪唑并[1,2- a ]吡啶环化的偶联伙伴。
Clarke, Journal of the Chemical Society, 1957, p. 3807