2876-13-3Relevant academic research and scientific papers
Novel hydrogen- and halogen-bonding anion receptors based on 3-iodopyridinium units
Amendola, Valeria,Bergamaschi, Greta,Boiocchi, Massimo,Fusco, Nadia,La Rocca, Mario Vincenzo,Linati, Laura,Lo Presti, Eliana,Mella, Massimo,Metrangolo, Pierangelo,Miljkovic, Ana
, p. 67540 - 67549 (2016)
Novel tripodal 3-iodopyridinium-based receptors were investigated through (i) UV-vis and NMR titrations with anions in solution, (ii) theoretical calculations, and (iii) X-ray diffraction studies. Their anion binding properties were compared to those of the monobranched model and/or non-halogenated model systems. Investigations in acetonitrile pointed out that the iodine atom in the meta position to pyridinium enhances anion affinity. According to computational studies, this effect seemed to depend on the electron-withdrawing nature of the iodine-substituents. Notably, 1:1 adducts were observed to form in solution with all the investigated anions. The strong de-shielding effect observed on the receptors' protons upon anion binding indicated their participation in hydrogen-bonds with the coordinated anion. This result was supported by theoretical calculations and, in the solid state, by X-ray diffraction studies on the complexes with nitrate and bromide. In the crystalline state, the pyridinium arms of the tripodal receptor assume a 2-up, 1-down conformation. Both nitrate and bromide anions are included in the receptor's cavity, forming two hydrogen-bonding interactions with the protons of the 2-up arms, and one halogen-bonding interaction with the C-I group of a second molecular cation. The combination of hydrogen and halogen bonds leads to supramolecular chains in the crystals.
Mechanistic study of laser desorption/ionization of small molecules on graphene oxide multilayer films
Kim, Young-Kwan,Min, Dal-Hee
, p. 12675 - 12683 (2014)
Graphene and graphene oxide (GO) films have been explored to develop an efficient laser desorption/ionization mass spectrometry (LDI-MS) platform for the analysis of chemically and biologically important small molecules. The GO films were prepared by layer-by-layer (LBL) assembly cycles (one to ten layers) with precisely controlled thickness and surface roughness which are important structural factors for laser energy absorption capacity and laser energy transfer for efficient LDI-MS analysis. Amino acids, saccharides, and pyrenylated molecules were analyzed by LDI-MS on the LBL assembled GO films to reveal their structural influence on LDI-MS analysis of small molecules. Then, the structural influence of LBL assembled GO films on synergistic effect was investigated to develop an efficient and widely applicable LDI-MS analysis platform with an additional multiwalled carbon nanotube (MWCNT) layer. We found that the optimum number of GO film layers for LDI-MS analysis was dependent on the chemical structures of small molecules, and the laser energy threshold needed for LDI of small molecules on GO/MWCNT films could be lowered as the number of LBL assembled GO films increased underneath the MWCNT layer.
Glutaconaldehyde as an Alternative Reagent to the Zincke Salt for the Transformation of Primary Amines into Pyridinium Salts
Asskar, Ghada,Rivard, Michael,Martens, Thierry
, p. 1232 - 1239 (2019/12/24)
In the presence of amines, the degradation of glutaconaldehyde in acidic medium can be prevented. By exploitation of this behavior, primary amines are transformed into their corresponding pyridinium salts, including those substrates that remain unreactive toward the Zincke salt, which is the reagent typically used to perform this transformation. The use of glutaconaldehyde also allows control of the nature of the counterion of the pyridinium with no need for additional salt metathesis reaction.
Application of primary halogenated hydrocarbons for the synthesis of 3-Aryl and 3-Alkyl indolizines
Liu, Yan,Hu, Huayou,Zhou, Junyu,Wang, Wenhui,He, Youliang,Wang, Chao
, p. 5016 - 5024 (2017/07/10)
Indolizine is an important heterocyclic compound with several interesting properties that make it suitable for numerous applications in many fields, such as biology, medicine and materials. However, the synthesis of 3-Alkyl indolizines from bulky primary halogenated alkanes has not yet been reported. Herein, a transition-metal-free synthetic route to 3-Aryl and 3-Alkyl indolizines from electron-deficient alkenes, pyridines and primary halogenated hydrocarbons has been reported for the first time using a tandem reaction. The key step of this method is the oxidative dehydrogenative aromatization of a tetrahydroindolizine intermediate with 2,2,6,6-Tetramethylpiperidine-N-oxyl (TEMPO) as the oxidant. The advantages of this protocol are its use of easily available and low-cost starting materials, the transition-metal-free conditions and its ready scalability.
S8-Mediated Cyclization of 2-Aminophenols/thiophenols with Arylmethyl Chloride: Approach to Benzoxazoles and Benzothiazoles
Gan, Haifeng,Miao, Dazhuang,Pan, Qiang,Hu, Renhe,Li, Xiaotong,Han, Shiqing
, p. 1770 - 1774 (2016/07/07)
A metal-free approach to benzazoles from arylmethyl chlorides and 2-mercaptan/2-hydroxyanilines using elemental sulfur as a traceless oxidizing agent has been developed. The reactions proceeded in good to excellent yields, exhibiting good functional groups tolerance and gram-scale ability. A key mechanistic investigation indicated that the key intermediate trisulfide 6, which was characterized by NMR, HRMS and crystal X-ray crystallography, was separated in the reaction prior to the formation of the product.
METHOD FOR SYNTHESIZING AMMONIUM SALT AND COMPOSITION OBTAINED BY INCORPORATING POLYSACCHARIDES INTO AMMONIUM SALT
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Paragraph 0028, (2016/12/22)
PROBLEM TO BE SOLVED: To provide a method for synthesizing an ammonium salt containing a quaternary ammonium salt in a shorter time than a conventionally known example and to provide a new composition containing an ammonium salt and polysaccharides such as cellulose or chitin. SOLUTION: There are provided: a method for synthesizing ammonium salt containing a quaternary ammonium salt in a shorter time than a conventionally known example; and a method for producing a new composition containing an ammonium salt and polysaccharides such as cellulose or chitin. COPYRIGHT: (C)2015,JPOandINPIT
Towards reaction control using an ionic liquid: Biasing outcomes of reactions of benzyl halides
Keaveney, Sinead T.,Harper, Jason B.
, p. 15698 - 15704 (2013/09/12)
The effect of the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide on substitution and elimination reactions of benzyl halides is examined and solvent control of the reaction outcome demonstrated. In competing reactions, the ionic liquid is shown to favour unimolecular processes over bimolecular processes and substitution over elimination, irrespective of the mole fraction of ionic liquid used. Temperature dependent analyses, where possible, are used to determine the microscopic origins of these effects.
High regiocontrol in the nucleophilic ring opening of 1-aralkyl-3,4- epoxypiperidines with amines - A short-step synthesis of 4- fluorobenzyltrozamicol and novel anilidopiperidines
Scheunemann, Matthias,Hennig, Lothar,Funke, Uta,Steinbach, J?rg
experimental part, p. 3448 - 3456 (2011/06/20)
Nucleophilic ring-opening reactions of three 1-aralkyl-3,4-epoxypiperidines with a series of aliphatic and aromatic amines have been investigated. Reactions in protic solvents, preferably 2-propanol, gave rise to 3-amino-piperidin-4-ols in ratios up to 20:1. Accordingly, 4- fluorobenzyltrozamicol, a highly potent ligand for the vesicular acetylcholine transporter was obtained directly from an epoxide ring opening in one step, without the need of chromatographic separation. Reactions in acetonitrile assisted by Li-salts, most suitable with LiBr, led regioselectively to trans-4-amino-piperidin-3-ols in high yields. N-Phenethyl substituted anilino-piperidinols as easily obtained by this method were converted into a series of new β-hydroxy substituted anilidopiperidines.
Assessment of the catalytic activities of novel broensted acidic ionic liquid catalysts
Srivastava, Rajendra
experimental part, p. 17 - 25 (2010/12/25)
Broensted acidic ionic liquids (BILs) were synthesized by a two step synthetic protocol. Catalytic activities of BILs were assessed by means of suitable catalytic reactions such as acylation of 2-methoxynapthalene with acetic anhydride, Biginelli reaction to synthesize 3,4-dihydropyrimidin-2(1H)- one, stereoselective synthesis of β-amino ketone via direct Mannich-type reaction and esterification of hexanoic acid with benzyl alcohol. Catalytic activities of BILs were high when compared with those of solid acid catalysts such as ZSM-5, beta, dealuminated beta and Al-SBA-15. BILs catalysts were found to be highly stereo/regio-selective for above mentioned reactions. Novel BILs catalyst offers several attractive features such as low cost, high catalytic activity/selectivity and recyclability. Graphical Abstract: N-methylimidazole and pyridine derived Broensted acidic ionic liquids were found to be highly active and stereo/regio-selective compared to various solid acid catalysts in fine chemicals (1-5) synthesis.[Figure not available: see fulltext.]
Graphene-based SELDI probe with ultrahigh extraction and sensitivity for DNA oligomer
Tang, Lena Ai Ling,Wang, Junzhong,Loh, Kian Ping
supporting information; experimental part, p. 10976 - 10977 (2010/09/17)
We demonstrate that graphene can be used as an ultrahigh efficiency preconcentration and detection platform for ssDNA. DNA-adsorbed graphene can be used directly for Surface Enhanced Laser Desorption Ionization-Time of Flight-Mass Spectrometry (SELDI-TOF-MS). The rapid enrichment of biomolecules and direct, label-free detection are potentially useful for analysis in proteomics and genomics.
