Xi:Irritant;
535-80-8Relevant academic research and scientific papers
Rapid Boulton–Katritzky rearrangement of 5-aryl-3-[2-(piperidin-1-yl)ethyl]-1,2,4-oxadiazoles upon exposure to water and HCl
Kayukova, Lyudmila A.,Uzakova, Asem B.,Vologzhanina, Anna V.,Akatan, Kydyrmolla,Shaymardan, Esbol,Kabdrakhmanova, Sana K.
, p. 643 - 649 (2018)
[Figure not available: see fulltext.] Сhemical stability of 3-(2-aminoethyl)-5-substituted 1,2,4-oxadiazoles was studied with respect to Boulton–Katritzky rearrangement, which is known to produce planar pyrazolines and pyrazoles upon heating in DMF at 150°C or without solvent at 240°C. The reactivity of 5-aryl-3-[2-(piperidin-1-yl)ethyl]-1,2,4-oxadiazoles in one type of Boulton–Katritzky rearrangement was observed at room temperature in H2O, DMF + H2O, and in the presence of HCl. Hydrolysis of 3,5-disubstituted 1,2,4-oxadiazoles under the first two conditions gave 2-amino-1,5-diazaspiro[4.5]dec-1-en-5-ium benzoates, while the action of HCl on 3,5-disubstituted 1,2,4-oxadiazoles produced their hydrochlorides along with 2-amino-1,5-diazaspiro[4.5]dec-1-en-5-ium chloride hydrate. Thus, the reaction afforded spiropyrazoline compounds instead of products with a planar structure.
2-Amino-3-methylpyridinium, 2-amino-4-methylbenzothiazolium and 2-amino-5-chloropyridinium salts. Experimental and theoretical findings
Braga, Ataualpa Albert Carmo,Hanif, Muhammad,Khalid, Muhammad,Khan, Ezzat,Morais, Sara Figueirêdo de Alcantara,Tahir, Muhammad Nawaz
, (2020)
Reaction between 2-amino-3-methylpyridine, 2-amino-4-methylbenzothiazole with salicylic acid, and 2-amino-5-chloropyridine with 3-chlorobenzoic acid were carried out and respective molecular salts 1–3 were obtained. During reactions, proton transfer from acid to endocyclic N of the base was observed. Structural elucidation of all compounds was carried out with the help of FT-IR and X-ray Diffraction for single crystals. The acid/base pairs in a molecular salt are held together with the help of H- and charge-assisted bonding and additional non-covalent bonding extend the supramolecular structure. All hydrogen bonds and secondary interactions have been discussed and a detailed comparison of experimental data with theoretical calculations through AIM, NBO and Wiberg bond index analysis has been made. The non-covalent character was mainly typified by positive values of Laplacian of electronic density. The theoretical studies demonstrate that other than classical H-bonds, the non-classical and secondary non-covalent interactions are very important to direct supramolecular structure of the respective molecular salt. The DFT calculations with solvent model SMD proved a good alternative to deduce the molecular salt formation when the 0>ΔpKa>3. Moreover, global reactivity descriptors (GRD) have been calculated utilizing the energies of FMOs. The calculated values for HOMO of compounds 1–3, -5.469, -5.642 and -6.435, respectively indicate that the compounds adopt the numerical order in terms of electron donation/Lewis basicity. The molecular salt formation is more feasible for heterosynthon 1 and least for 3.
LIQUID CRYSTAL MIXTURE AND LIQUID CRYSTAL DISPLAY
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, (2022/04/09)
The invention relates to a compound of formula I, wherein R11, R21, A11, A, Z, X11, X21, Y11, Y12, Sp11, Sp21, o and p have one of the meanings as given in claim 1. The invention further relates to method of production of a compound of formula I, to the use of said compounds in LC media and to LC media comprising one or more compounds of formula I. Further, the invention relates to a method of production of such LC media, to the use of such media in LC devices, and to LC device comprising a LC medium according to the present invention. The present invention further relates to a process for the fabrication such liquid crystal display and to the use of the liquid crystal mixtures according to the invention for the fabrication of such liquid crystal display.
Efficiency of lithium cations in hydrolysis reactions of esters in aqueous tetrahydrofuran
Harada, Yumi,Hayashi, Kazuhiko,Ichimaru, Yoshimi,Imai, Masanori,Kojima, Yuki,Maeda, Azusa,Nakayama, Kanae,Sugiura, Kirara
, p. 581 - 594 (2021/06/06)
Lithium cations were observed to accelerate the hydrolysis of esters with hydroxides (KOH, NaOH, LiOH) in a water/tetrahydrofuran (THF) two-phase system. Yields in the hydrolysis of substituted benzoates and aliphatic esters using the various hydroxides were compared, and the effects of the addition of lithium salt were examined. Moreover, it was presumed that a certain amount of LiOH was dissolved in THF by the coordination of THF with lithium cation and hydrolyzed esters even in the THF layer, as in the reaction by a phase-transfer catalyst.
Combining photoredox catalysis and oxoammonium cations for the oxidation of aromatic alcohols to carboxylic acids
Nandi, Jyoti,Hutcheson, Ellen L.,Leadbeater, Nicholas E.
supporting information, (2020/12/25)
A methodology is reported for converting alcohols to the corresponding carboxylic acids. A dual catalytic system involving a merger of photoredox catalysis and 4-acetamido-TEMPO is employed to carry out this oxidation process.
Aerobic oxidation of aldehydes to carboxylic acids catalyzed by recyclable ag/c3 n4 catalyst
Wu, Chaolong,Yao, Xiaoquan,Yu, Min,Zhou, Li,Zhu, Li
, p. 167 - 175 (2021/03/19)
The oxidation of aldehydes is an efficient methodology for the synthesis of carboxylic acids. Herein we hope to report a simple, efficient and recyclable protocol for aerobic oxidation of aldehydes to carboxylic acid by using C3N4 supported silver nanoparticles (Ag/C3N4) as a catalyst in aqueous solution under mild conditions. Under standard conditions, the corresponding carboxylic acids can be obtained in good to excellent yields. In addition, Ag/C3N4 is convenient for recovery and could be reused three times with satisfactory yields.
One-Pot Direct Oxidation of Primary Amines to Carboxylic Acids through Tandem ortho-Naphthoquinone-Catalyzed and TBHP-Promoted Oxidation Sequence
Kim, Hun Young,Oh, Kyungsoo,Si, Tengda
supporting information, p. 18150 - 18155 (2021/12/09)
Biomimetic oxidation of primary amines to carboxylic acids has been developed where the copper-containing amine oxidase (CuAO)-like o-NQ-catalyzed aerobic oxidation was combined with the aldehyde dehydrogenase (ALDH)-like TBHP-mediated imine oxidation protocol. Notably, the current tandem oxidation strategy provides a new mechanistic insight into the imine intermediate and the seemingly simple TBHP-mediated oxidation pathways of imines. The developed metal-free amine oxidation protocol allows the use of molecular oxygen and TBHP, safe forms of oxidant that may appeal to the industrial application.
Photo-induced deep aerobic oxidation of alkyl aromatics
Wang, Chang-Cheng,Zhang, Guo-Xiang,Zuo, Zhi-Wei,Zeng, Rong,Zhai, Dan-Dan,Liu, Feng,Shi, Zhang-Jie
, p. 1487 - 1492 (2021/07/10)
Oxidation is a major chemical process to produce oxygenated chemicals in both nature and the chemical industry. Presently, the industrial manufacture of benzoic acids and benzene polycarboxylic acids (BPCAs) is mainly based on the deep oxidation of polyalkyl benzene, which is somewhat suffering from environmental and economical disadvantage due to the formation of ozone-depleting MeBr and corrosion hazards of production equipment. In this report, photo-induced deep aerobic oxidation of (poly)alkyl benzene to benzene (poly)carboxylic acids was developed. CeCl3 was proved to be an efficient HAT (hydrogen atom transfer) catalyst in the presence of alcohol as both hydrogen and electron shuttle. Dioxygen (O2) was found as a sole terminal oxidant. In most cases, pure products were easily isolated by simple filtration, implying large-scale implementation advantages. The reaction provides an ideal protocol to produce valuable fine chemicals from naturally abundant petroleum feedstocks. [Figure not available: see fulltext.].
Oxidative α-C-C Bond Cleavage of 2° and 3° Alcohols to Aromatic Acids with O2at Room Temperature via Iron Photocatalysis
Zhang, Zongnan,Zhang, Guoxiang,Xiong, Ni,Xue, Ting,Zhang, Junjie,Bai, Lu,Guo, Qinyue,Zeng, Rong
supporting information, p. 2915 - 2920 (2021/05/05)
The selective α-C-C bond cleavage of unfunctionalized secondary (2°) and tertiary alcohols (3°) is essential for valorization of macromolecules and biopolymers. We developed a blue-light-driven iron catalysis for aerobic oxidation of 2° and 3° alcohols to acids via α-C-C bond cleavages at room temperature. The first example of oxygenation of the simple tertiary alcohols was reported. The iron catalyst and blue light play critical roles to enable the formation of highly reactive O radicals from alcohols and the consequent two α-C-C bond cleavages.
Selective oxidation of alkenes to carbonyls under mild conditions
Huo, Jie,Xiong, Daokai,Xu, Jun,Yue, Xiaoguang,Zhang, Pengfei,Zhang, Yilan
supporting information, p. 5549 - 5555 (2021/08/16)
Herein, a practical and sustainable method for the synthesis of aldehydes, ketones, and carboxylic acids from an inexpensive olefinic feedstock is described. This transformation features very sustainable and mild conditions and utilizes commercially available and inexpensive tetrahydrofuran as the additive, molecular oxygen as the sole oxidant and water as the solvent. A wide range of substituted alkenes were found to be compatible, providing the corresponding carbonyl compounds in moderate-to-good yields. The control experiments demonstrated that a radical mechanism is responsible for the oxidation reaction.
