2789-89-1Relevant articles and documents
Synthesis and thermal properties of an acetylenic monomer containing boron and silicon
Cheng, Shengli,Zong, Lishuai,Yuan, Kuanyu,Han, Jianhua,Jian, Xigao,Wang, Jinyan
, p. 88403 - 88410 (2016)
To improve the thermo-oxidative stability of acetylenic aromatic compounds, 1,2-bis(4-trimethylsilylethynylphenyl)-carborane (CBTMS) was designed, synthesized and characterized by FT-IR, 1H-NMR, 13C-NMR and mass spectrometry. The analysis of the DSC results showed that the acetylenic monomer had a melting point at 195.5 °C. The cross-linking process of CBTMS included a Diels-Alder cycloaddition reaction confirmed by FT-IR spectroscopy. Nonisothermal DSC studies showed CBTMS has an activation energy similar to that of the phenylethynyl-terminated compound. The thermoset and ceramic derived from the acetylenic monomer exhibited extremely thermo-oxidatively stable properties studied using thermogravimetric analysis (TGA). The thermoset showed a weight gain in air at elevated temperature and char yield of 98.8% at 1000 °C in air, and the ceramic residue had almost no weight loss up to 1000 °C in air. We demonstrated that trimethylsilylethynyl could be used as a crosslinking group for thermosetting polymers.
Mechanochemical Synthesis of Diarylethynes from Aryl Iodides and CaC 2
Bolm, Carsten,Van Bonn, Pit
supporting information, (2022/02/25)
A mechanochemical synthesis of diarylethynes from aryl iodides and calcium carbide as acetylene source is reported. The reaction is catalyzed by a palladium catalyst in the presence of copper salt, base, and ethanol as liquid assisting grinding (LAG) additive. Various aryl and heteroaryl iodides have been converted in up to excellent yields.
Iodonium Cation-Pool Electrolysis for the Three-Component Synthesis of 1,3-Oxazoles
Sattler, Lars E.,Hilt, Gerhard
, p. 605 - 608 (2020/12/07)
The synthesis of 1,3-oxazoles from symmetrical and unsymmetrical alkynes was realized by an iodonium cation-pool electrolysis of I2 in acetonitrile with a well-defined water content. Mechanistic investigations suggest that the alkyne reacts with the acetonitrile-stabilized I+ ions, followed by a Ritter-type reaction of the solvent to a nitrilium ion, which is then attacked by water. The ring closure to the 1,3-oxazoles released molecular iodine, which was visible by the naked eye. Also, some unsymmetrical internal alkynes were tested and a regioselective formation of a single isomer was determined by two-dimensional NMR experiments.
Selective Synthesis of Non-Aromatic Five-Membered Sulfur Heterocycles from Alkynes by using a Proton Acid/N-Chlorophthalimide System
Yu, Wentao,Zhu, Baiyao,Shi, Fuxing,Zhou, Peiqi,Wu, Wanqing,Jiang, Huanfeng
supporting information, p. 1313 - 1322 (2020/12/01)
A multicomponent strategy to achieve two different regioselectivities from alkynes, isothiocyanates and H2O with a proton acid/N-chlorophthalimide (NCPI) system is described to selectively obtain non-aromatic five-membered sulfur heterocycles (1,3-oxathiol-2-imines/thiazol-2(3H)-one derivatives) through multiple bond formations. The process features readily available starting materials, mild reaction conditions, broad substrate scope, good functional-group tolerance, high regio- and chemo- selectivities, gram-scale synthesis and late-stage modifications. Mechanistic studies support the proposal that the transformation process includes a combination of H2O and isothiocyanate, free-radical formation, carbonation and intramolecular cyclization to give the products. Furthermore, the 1,3-oxathiol-2-imine derivatives possess unique fluorescence characteristics and can be used as Pd2+ sensors with a “turn-off” response, demonstrating potential applications in environmental and biological fields.
