Synthesis of new malonaldehyde derivatives using 2-heteroaryl-substituted trimethinium salts
摘要:
A synthetic route for obtaining 2-heteroaryl-substituted zwitterionic malonaldehydes 1c-6c is described. The synthesis involves the two-fold formylation of heteroarylacetic acids 1a-6a using the Vilsmeier-Haack reagent, followed by hydrolysis of the intermediate trimethinium salts 1b-6b with aqueous sodium carbonate. Elemental analysis, IR, H-1 NMR, C-13 NMR, and mass spectral data confirm the structures of the newly synthesized compounds. (C) 2012 Elsevier Ltd. All rights reserved.
Synthesis of polynuclear heterocycles via the reaction of α-ester carbanions with quaternized nicotinamide salts. A facile stereoselective synthesis of sesbanine
A Novel and Practical Synthesis of 3-Unsubstituted Indolizines
作者:Lande Zhang、Feng Liang、Lingzhi Sun、Yuefei Hu、Hongwen Hu
DOI:10.1055/s-2000-8195
日期:——
A novel and practical procedure for the preparation of 3-unsubstituted indolizines by 1,3-dipolar cycloaddition was developed. The requisite pyridinium N-methylides were generated simply from the corresponding N-(carboxymethyl)pyridinium halides. In the presence of MnO2, electron-deficient alkenes, instead of alkynes or vinyl bromides, were used successfully as dipolarophiles. This general method features cheap reagents, simple workup procedure and gives the products in moderate to high yields (57-92%).
Synthesis, structural/photophysical characterization and theoretical investigations with new β-pyridinium/quinolinium and β-bromine substituted bis(1,3-dimethylbarbituric acid) trimethine oxonol dyes that display large Stokes shifts
作者:Fereshteh Azamifar、M. Reza Naimi-Jamal、Ardeshir Rineh、Michael J. Kelso
DOI:10.1016/j.dyepig.2019.107758
日期:2020.1
photophysical properties of dye 3a in a series of organic solvents with different polarity confirmed intramolecular charge transfer (ICT). Optimized geometries of the synthesized dyes in the ground state calculated using density functional theory (DFT) at the B3LYP/6-311G(d,p) theory level identified that planar cis and trans configurations were preferred for the pyridinium/quinolinium and bromine substituted
开发了一种有效的三步法,用于合成新型β-吡啶鎓/喹啉鎓/溴取代的双(1,3-二甲基巴比妥酸)三甲氧肟酸染料,该方法涉及简单的三乙胺促进的1,3-二甲基巴比妥酸与三乙胺的缩合反应。预制的vinamidinium盐。1 H NMR,13 C NMR,IR和质谱数据证实了染料的结构。染料在CH 3 CN中的溶液分别在467–480 nm和531–712 nm范围内显示出最大的吸收和荧光发射,这表明染料显示出异常大的斯托克斯位移(〜230 nm)。研究染料3a的光物理性质在一系列具有不同极性的有机溶剂中证实了分子内电荷转移(ICT)。在B3LYP / 6-311G(d,p)理论水平上使用密度泛函理论(DFT)计算的基态合成染料的最佳几何形状确定了吡啶/喹啉鎓和溴取代的染料优选平面顺式和反式构型, 分别。TD-DFT对染料激发态结构的计算表明,松弛过程中笨重的吡啶鎓取代基的旋转是造成较大斯托克斯位移
Facile synthesis of novel 3-substituted pyrido[1,2-a]pyrimidinium salts using vinamidinium salts
ABSTRACT Pyrido[1,2-a]pyrimidinium salt derivatives 2a–f were prepared in good yields by condensation of 2-aminopyridine with 2-substituted vinamidinium salt derivatives 1a–f. The purity and the structure of the synthetized compounds were ascertained by elemental analysis, mass spectrometry, infrared, and NMR (¹H and ¹³C 400 MHz) spectroscopy. GRAPHICAL ABSTRACT
study, an efficient method for the synthesis of new cyclophanes (5a-f, 6a-g) through the condensation of 1,4-phenylenedimethanamine (3) or 2,3,5,6-tetramethylbenzene-1,4-diamine (4) with 2-substituted vinamidiniums (2a-g) is described. The cyclophane derivatives are obtained in good to excellent yields in the presence of acetic acid in refluxing acetonitrile after 15 h. The structure of new compounds