نتایج جستجو برای: Activated acetylenes
تعداد نتایج: 222145 فیلتر نتایج به سال:
An efficient method to synthesis the 2H-pyrans using three component reactions of dithiocarbamats, activated acetylenes and isocyanides in water as the solvent is described. In these reactions, synthesis of 2H-pyrans is possible based on the one-pot reaction and without using any catalyst. The mild reaction conditions and high yields of the products exhibit synthetic advantage of these methods.
The structure-activity relationship of 12 isolated acetylenes from galls of Hedera rhombea (Araliaceae) induced by Asphondylia sp. (Cecidomyiidae) and their derivatives has been studied for the inhibition of the shoot and root growth of rice, perennial ryegrass, cockscomb, lettuce, and cress. Almost all acetylenes generally showed growth inhibitory activity. The diacetylenes exhibited higher ac...
Rhenium complex, [ReBr(CO)3(thf)]2-catalyzed reactions between aromatic imines and either acetylenes or α,β-unsaturated carbonyl compounds gave indene derivatives in good to excellent yields. These reactions proceed via C–H bond activation, insertion of acetylenes or α,β-unsaturated carbonyl compounds, intramolecular nucleophilic cyclization, and reductive elimination. Indene derivatives were a...
Imidazolium-based ionic liquids (ILs) bearing an alkylphosphite anion, were highly efficient for the selective removal of acetylenes in olefins. Comparison of solubility data at 313 K and at atmospheric pressure shows that the solubilities of acetylene and propyne in 1,3-dimethylimidazolium methylphosphite ([DMIM][MeHPO(3)]) are about 45 and 20 times higher than those of ethylene and propylene,...
In addition to the well-established nucleophilic alkynylation, the use of electrophilic alkynes can expand tremendously the scope of acetylene transfer reactions. The use of metal catalysis has recently led to a rebirth of this research area. Halogenoalkynes, hypervalent alkynyliodoniums, acetylene sulfones and in situ oxidized terminal acetylenes are the most often used reagents for electrophi...
The stable phosphonate derivatives have easily synthesized by the reactions involving trialkyl(aryl) phosphites and dimethyl acetylenedicarboxylate in the presence of 4-nitrophenol and/or acid chlorides, dialkyl(aryl) phosphites and N-methylimidazole at 70 oC under solventfree conditions.
An efficient synthesis of vinylphosphonates is described. This involves the reaction of alkyl cyanoformates and dialkyl acetylendicarboxylates in the presence of trialkyl phosphites. The 1H, 13C NMR, and 31P NMR spectra of vinylphosphonates having different substitution are consistent with the presence of two geometrical isomers.
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