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Phenylacetylene is a prototypical terminal acetylene, undergoing many reactions expected of that functional group. It undergoes semi hydrogenation over Lindlar catalyst to give styrene . In the presence of base and copper(II) salts, it undergoes oxidative coupling to give diphenylbutadiyne . [ 6 ]
Yet another method involves the coupling of iodobenzene and the copper salt of phenylacetylene in the Castro-Stephens coupling. The related Sonogashira coupling involves the coupling of iodobenzene and phenylacetylene. Diphenylacetylene is a planar molecule. The central C≡C distance is 119.8 picometers. [1]
A 3D model of ethyne (), the simplest alkyneIn organic chemistry, an alkyne is an unsaturated hydrocarbon containing at least one carbon—carbon triple bond. [1] The simplest acyclic alkynes with only one triple bond and no other functional groups form a homologous series with the general chemical formula C n H 2n−2.
The Hay coupling is variant of the Glaser coupling. It relies on the TMEDA complex of copper(I) chloride to activate the terminal alkyne. Oxygen (air) is used in the Hay variant to oxidize catalytic amounts of Cu(I) to Cu(II) throughout the reaction, as opposed to a stoichiometric amount of Cu(II) used in the Eglington variant. [7]
Propyne exists in equilibrium with propadiene, the mixture of propyne and propadiene being called MAPD: = = The coefficient of equilibrium K eq is 0.22 at 270 °C or 0.1 at 5 °C.
For example, acetylation of histones by histone acetyltransferases (HATs) results in an expansion of local chromatin structure, allowing transcription to occur by enabling RNA polymerase to access DNA. However, removal of the acetyl group by histone deacetylases (HDACs) condenses the local chromatin structure, thereby preventing transcription. [9]
Among the cross-coupling reactions it follows in the number of publications right after Suzuki and Heck reaction [8] and a search for the term "Sonogashira" in SciFinder provides over 1500 references for journal publications between 2007 and 2010. [7]
A variety of methods have been developed to synthesize polyacetylene. One of the most common methods is via passing acetylene gas over a Ziegler–Natta catalyst, such as Ti(OiPr) 4 /Al(C 2 H 5) 3. This method allows control over the structure and properties of the final polymer by varying temperature and catalyst loading. [13]