529-81-7Relevant academic research and scientific papers
An unusual synthesis of Troeger's bases using DMSO/HCl as formaldehyde equivalent
Li, Zhong,Xu, Xiaoyong,Peng, Yanqing,Jiang, Zhaoxing,Ding, Chuanyong,Qian, Xuhong
, p. 1228 - 1230 (2005)
The reactions between anilines and DMSO/HCl produce Troeger's bases in moderate yield. The Troeger's bases bearing an electron-withdrawing group can also be synthesized through this procedure. In this reaction, DMSO/HCl acts as formaldehyde equivalent. Ge
Bis-ortho-substitution by methyl groups dramatically increases the racemization barrier of Troeger bases
Lenev, Denis A.,Lyssenko, Konstantin A.,Golovanov, Denis G.,Buss, Volker,Kostyanovsky, Remir G.
, p. 6412 - 6418 (2006)
We have shown through racemization kinetics studies that the enantiomerization barriers of the bis-ortho-methyl substituted Troeger bases 2 and 3 in acidic media are raised by 30 kJ mol-1 relative to the parent compound 1, that is 130.4(4) and 131.6(4) kJ mol-1, respectively (105°C, pH 1, ethylene glycol). The enantiomerization barrier of para-meihoxy-para-nitro substituted Troeger base 4 was determined by dynamic capillary electrophoresis to 96.3(2) kJ mol-1 (25°C, pH 2.2, H2O), which is lower by 5 kJ mol-1 relative to 1. The influence of deutero-substitution on the racemization rates was also studied. The influence of steric and electronic factors on the enantiomerization barrier was investigated by quantum-mechanical (DFT) calculations. It is shown that enantiomerization takes place in two steps: ring-opening and further inter-conversion of the monocyclic intermediate. For the interconversion to occur a transition state has to be passed which is sensitive to steric effects. Ortho-substitution by methyl groups significantly increases the energy of this state. Thus, compounds 2 and 3 are the simplest Troeger bases which are configurationally stable in acidic media.
The mechanism of Troeger's base formation probed by electrospray ionization mass spectrometry
Abella, Carlos A. M.,Benassi, Mario,Santos, Leonardo S.,Eberlin, Marcos N.,Coelho, Fernando
, p. 4048 - 4054 (2007)
(Chemical Equation Presented) Using direct infusion electrospray ionization mass and tandem mass spectrometric experiments [ESI-MS(/MS)], we have performed on-line monitoring of some reactions used to form Troeger's bases. Key intermediates, either as cationic species or as protonated forms of neutral species, have been intercepted and characterized. The role of urotropine as the methylene source in these reactions has also been accessed. Reaction pathways shown by ESI-MS(/MS) have been probed by gas-phase ion/molecule reactions, and an expanded mechanism for Troeger's base formation based on the mass spectrometric data has been elaborated.
One-step synthesis of trger's base hybrids containing at least one halogen atom
Faroughi, Masoud,Zhu, Kai-Xian,Jensen, Paul,Craig, Donald C.,Try, Andrew C.
, p. 4266 - 4272 (2009)
The one-step synthesis of a series of hybrid dibenzo Trger's base analogues bearing at least one halogen atom is described. The strategy involves a reaction between two different anilines and affords hybrid compounds in yields as high as 46%, together with the symmetric Trger's base products. This straightforward approach requires only one chromatographic step and has the potential to replace multi-step approaches to hybrid Trger's base compounds. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009.
Design and synthesis of a novel banana-shaped functional molecule via double cross-coupling
Yang, Bingchuan,Shen, Guodong,Huang, Xianqiang,Liu, Rutao
, (2019)
A novel banana-shaped molecule using 2,8-Dimethyl-6H,12H-5,11-methanodibenzo [b,f] [1,5]diazocine (Tr?ger’s base) as bent-core was synthesized via double Carbon-Carbon cross-coupling reaction. The double Sonogashira cross-coupling reaction was optimized by using Pd(PPh3)2Cl2 as catalyst, CuI as cocatalyst and diisopropylamine as base in place of triethylamine. The structure of this compound was confirmed by 1H-NMR, 13C-NMR, Fourier transform infrared (FT-IR) spectroscopy and mass spectrometry.
Synthetic routes to linear Oligo-Troeger's bases
Dolensky, Bohumil,Valik, Martin,Sykora, David,Kral, Vladimir
, p. 67 - 70 (2005)
(Chemical Equation Presented) Derivatives of Troeger's base (TB) have played important roles in receptor construction due to their rigid V-shape. A new class of these compounds are the oligo-TBs, which can function as cavitands. Herein, we describe both stepwise and one-step (oligomerization) methods suitable for the preparation of linear oligo-TBs.
HPLC with cellulose Tris (3,5-DimethylPhenylcarbamate) chiral stationary phase: Influence of coating times and coating amount on chiral discrimination
Wei, Qiuhong,Su, Hongjiu,Gao, Diannan,Wang, Shudong
, p. 164 - 173 (2019/01/18)
Coating cellulose tris (3,5-dimethylphenylcarbamate) (CDMPC) on silica gels with large pores have been demonstrated as an efficient way for the preparation of chiral stationary phase (CSP) for high-performance liquid chromatography (HPLC). During the process, a number of parameters, including the type of coating solvent, amount of coating, and the method for subsequent solvent removing, have been proved to affect the performance of the resultant CSPs. Coating times and the concentration of coating solution, however, also makes a difference to CSPs' performance by changing the arrangement of cellulose derivatives while remaining the coating amount constant, have much less been studied before, and thereby, were systematically investigated in this work. Results showed that CSPs with more coating times exhibited higher chiral recognition and column efficiency, suggesting that resolution was determined by column efficiency herein. Afterwards, we also investigated the effect of coating amount on the performance of CSPs, and it was shown that the ability of enantio-recognition did not increase all the time as the coating amount; and four of seven racemates achieved best resolution when the coating amount reached to 18.37%. At the end, the reproducibility of CDMPC-coated CSPs were further confirmed by two methods, ie, reprepared the CSP-0.15-3 and reevaluated the effect of coating times.
Synthesis of new cyano-substituted analogues of Tr?ger's bases from bromo-derivatives. A stereochemical dependence of long-range (nJHH, n?=?4, 5, and 6) proton–proton and proton–carbon (nJCH, n?=?1, 2, 3, 4, and 5) coupling constants of these compounds
Dusso, Diego,Ramirez, Cristina,Parise, Alejandro,Lanza,Vera, D. Mariano,Chesta, Carlos,Moyano, E. Laura,Akhmedov, Novruz G.
, p. 423 - 454 (2019/05/24)
A free-catalyst microwave-assisted cyanation of brominated Tr?ger's base derivatives (2a-f) is reported. The procedure is simple, efficient, and clean affording the nitrile compounds (3a-e, I) in very good yields. Complete assignment of 1H and 13C chemical shifts of 2a-f, I and 3a-d, I was achieved using gradient selected 1D nuclear magnetic resonance (NMR) techniques (1D zTOCSY, PSYCHE, DPFGSE NOE, and DEPT), homonuclear 2D NMR techniques (gCOSY and zTOCSY), and heteronuclear 2D NMR techniques (gHSQCAD/or pure-shift gHSQCAD, gHMBCAD, bsHSQCNOESY, and gHSQCAD-TOCSY) with adiabatic pulses. Determination of the long-range proton–proton coupling constants nJHH (n?=?4, 5, 6) was accomplished by simultaneous irradiation of two protons at appropriate power levels. In turn, determined coupling constants were tested by an iterative simulation program by calculating the 1H NMR spectrum and comparing it to the experimental spectrum. The excitation-sculptured indirect-detection experiment (EXSIDE) and 1H-15N CIGARAD-HMBC (constant time inverse-detection gradient accordion rescaled heteronuclear multiple bond correlation) were applied for determination of long-range carbon–proton coupling constants nJCH (n?=?2, 3, and 4) and for assignment of 15N chemical shift at natural abundance, respectively. DFT/B3LYP optimization studies were performed in order to determine the geometry of 2c using 6-31G(d,p), 6-311G(d,p), and 6–311?+?G(d,p) basis sets. For calculation of 1H and 13C chemical shifts, nJHH (n?=?2, 3, 4, 5, and 6), and nJCH (n?=?1, 2, 3, and 4) coupling constants, the GIAO method was employed at the B3LYP/6-31G(d,p), B3LYP/6-31+G(d,p), B3LYP/6-311+G(d,p), B3LYP/6-311++G(2d,2p), B3LYP/cc-pVTZ), and B3LYP/aug-cc-pVTZ) levels of theory. For the first time, a stereochemical dependence magnitude of the long-range nJHH (n?=?4, 5, and 6) and nJCH (n?=?1, 2, 3, 4, and 5) have been found in bromo-substituted analogues of Tr?ger's bases.
Synthesis of quinolines from anilines, acetophenones and DMSO under air
Jiang, Tao-Shan,Wang, Xi,Zhang, Xiuli
, p. 2979 - 2982 (2018/06/29)
An efficient CH3SO3H-promoted synthesis of quinolines from readily available anilines, acetophenones and DMSO under air is reported. This protocol gives diverse substituted 4-arylquinolines in moderate to high yields with broad substrate/functional group tolerance. Preliminary mechanistic studies demonstrate that DMSO may be transformed to HCHO in this process and used as a one carbon source.
Preparation and evaluation of regioselectively substituted amylose derivatives for chiral separations
Tang, Shouwan,Jin, Zhaolei,Sun, Baishen,Wang, Fang,Tang, Wenyuan
, p. 512 - 521 (2017/08/26)
Six novel regioselectively substituted amylose derivatives with a benzoate at 2-position and two different phenylcarbamates at 3- and 6-positions were synthesized and their structures were characterized by 1H nuclear magnetic resonance (NMR) spectroscopy. Their enantioseparation abilities were then examined as chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC) after they were coated on 3-aminopropyl silica gels. Investigations indicated that the substituents at the 3- and 6-positions played an important role in chiral recognition of these amylose 2-benzoate serial derivatives. The derivatives demonstrated characteristic enantioseparation and some racemates were better resolved on these derivatives than on Chiralpak AD, which is one of the most efficient CSPs, utilizing coated amylose tris(3,5-dimethylphenylcarbamate) as the chiral selector. Among the derivatives prepared, amylose 2-benzoate-3-(phenylcarbamate/4-methylphenylcarbamate)-6-(3,5-dimethylphenylcarbamate) exhibited chiral recognition abilities comparable to that of Chiralpak AD and may be useful CSPs in the future. The effect of mobile phase on chiral recognition was also studied. In general, with the decreased concentration of 2-propanol, better resolutions were obtained with longer retention times. Moreover, when ethanol was used instead of 2-propanol, poorer resolutions were often achieved. However, in some cases, improved enantioselectivity was achieved with ethanol rather than 2-propanol as the mobile phase modifier.
