A novel catalytic system for homocoupling terminal acetylenes was elaborated based on CuCl as a catalyst (10 mol%), TMEDA as a base and CCl4 as an oxidant. The influence of the solvent, base, amount of catalyst and CCl4 on the reaction was investigated. Methanol was found to be the solvent of choice. The broad synthetic scope of the reaction was demonstrated. Diynes with various substituents were prepared in up to 92% yields. The possible reaction mechanism is discussed.
The protocol, 3-methyldec-1-yn-3-ol (1a) was chosen to perform the dimerization process. The optimal conditions for synthesis of 8,13-dimethylicosa-9,11-diyne-8,13 (2a) with high efficiency when using copper-catalyzed, N,N,N′N′-tetramethylethylenediamine as a ligand and CCl4 and methanol solvents in atmospheric pressure were determined. The structure of the obtained compound was proved by IR, 1H-NMR and 13C-NMR spectroscopy.
In this work, various aromatic monocarboxylic and dicarboxylic acids were subjected for the first time to a vinylation reaction with acetylene under heterogeneous catalytic conditions using catalytic systems based on silicon oxycarbide supported on silicon carbide (SiC): zinc silicon oxycarbide (Zn/SiOC), zinc oxide silicon oxycarbide (ZnO/SiOC), and nickel silicon oxycarbide (Ni/SiOC). The influence of the nature of the starting materials, temperature, reaction duration, solvent, and catalyst type on the yield of vinyl esters was investigated. The vinylation reaction of aromatic carboxylic acids with acetylene was carried out at 1:2 molar ratio, using a Zn/SiOC-50 catalytic system at a loading of 10 mol% relative to the initial aromatic carboxylic acid, in a N,N-dimethylformamide (DMF) solution at 150 °C for 12 h, resulting in high yields of vinyl esters. Under these heterogeneous catalytic conditions, the vinylation reaction afforded the following vinyl esters: benzoic acid (80%), 4-methylbenzoic acid (77%), 4-methoxybenzoic acid (70%), 4-fluorobenzoic acid (83%), 4-tert-butylbenzoic acid (65%), 4-chlorobenzoic acid (85%), divinyl esters of ortho-phthalic acid (88%), and terephthalic acid (91%). The structures of the synthesized vinyl esters were confirmed by Fourier-transform infrared (FTIR), proton nuclear magnetic resonance (1H NMR), carbon-13 nuclear magnetic resonance (13C NMR), and chromatographic-mass spectral (MS) analyses.
20 June 2019 in Chemistry and Chemical Engineering
Synthesis of new biologically-active acetylene alcohols containing in composition of their molecules aromatical, cyclical and hydroxyl-groups and also triple bond by reaction of enantioselective alkylation of some cyclic ketones such as cyclohexanon, 2-methylcyclohexanon, menton and camphora with phenylacetylene in the presence of 3,3′-diphenylbinaphtol has been investigated. New methods of synthesis of acetylene alcohols and mechanisms of corresponding reactions were preposed. Influence of nature of initial compounds, catalysts and solvents on carring out of reaction and yields of products has been determined. On the base experimental results optimal condition of carring out of reactions have been also determined. It was shown that in solution of TGF the mole ratio phenylacetylene: keton 1:2, temperatupe 0 oC, duration of reaction 120 min. are the optimal conditions of carring out of investigated reactions. Structure of synthesized alcohols: 1-(2-phenylethynil)cyclohexanol, 2-methyl-1-(2- phenylethynil)-cyclohexanol, 2-isopropyl-5-methyl-1-(2-phenylethynil)cyclohexanol and 1,7,7-threemethyl-2-(2-phenylethynil) biciclo[2,2,1]-heptanol-2 has been proved and also their purity was determined by some physico-chemical methods.
2 June 2023 in Acta Crystallographica Section E Crystallographic Communications
The title compound, C16H22O2, was synthesized in order to obtain its guest-free form because `wheel-and-axle'-shaped molecules tend to crystallize from solutions as solvates or host–guest molecules. It crystallizes in the monoclinic space group P2/c with two crystallographically non-equivalent molecules, one situated on an inversion center and the other on a twofold axis. The rod-like 1,3-diyne fragments have the usual linear geometry. In the crystal, O—H ... O bonds form eight-membered rings of the R44(8) type, linking molecules into layers. The Hirshfeld surface analysis indicates that the largest contributions are from intermolecular H...H (ca 71%) and H...C/C...H (ca 19%) contacts. The energies of the frontier molecular orbitals were determined by DFT calculations at the B3LYP/def2-TZVP level of theory.
20 December 2019 in Chemistry and Chemical Engineering
The synthesis of acetylene alcohol 1,3-diphenyl propin-2-ol-1, which has several reaction centers in the molecule, is studied. This product was obtained for the first time from a representative of aromatic hydrocarbons of benzaldehyde with phenylacetylene based on an alkynylation reaction in the presence of stereoselective catalysts - ZnEt2/Ti(OiPr)4/PhMe and Sn(OTf)2/NEt3/MeCN. The influence of the activity, stability, and selectivity of the selected catalysts on the yield of products, as well as, the rate of the main reactions, along with side reactions was analyzed. The optimal conditions for the alkynylation reaction and the selectivity of the process are determined. The main and by-products formed in this process are identified. Suggestions are made for the formation of unstable intermediate compounds - carbcations, carbanions, radicals, as well as, active complexes of reactions and catalytic modifications formed in the transition state. A number of efficiencies have been developed for catalysts for the enantoselective alkynylation reaction.