An iterative approach toward the synthesis of discrete oligomeric p-phenylene vinylene organic dyes employing aqueous Wittig chemistry
摘要:
Photovoltaic research has become increasingly prominent as the search for alternatives to fossil fuels are actively sought. A novel process for the iterative synthesis of discrete donor/acceptor-flanked oligostilbenes, key constituents in dye-sensitized solar cells, is described. The aqueous Wittig process is high yielding, proceeds with high (E)-stereoselectivity and allows facile product purification. (C) 2011 Elsevier Ltd. All rights reserved.
Ring‐Closing Olefin Metathesis Catalyzed by Well‐Defined Vanadium Alkylidene Complexes
作者:Dmitry S. Belov、Gabriela Tejeda、Charlene Tsay、Konstantin V. Bukhryakov
DOI:10.1002/chem.202005438
日期:2021.3.8
selectivity in ring‐opening metathesis polymerization of strained cyclic olefins comparable to those of Ru, Mo, and W catalysts. However, the application of V alkylidenes in routine organic synthesis is limited. Here, we present the firstexample of ring‐closing olefin metathesis catalyzed by well‐defined V chloride alkylidene phosphine complexes. The developed catalysts exhibit tolerance to various functional
A two-step pathway for preparing high pure quaternary phosphonium salts is disclosed. In the first step, hydrogen phosphide (PH
3
) or a higher phophine reacts with a protonic compound to produce a phosphonium salt, which then reacts with a carbonic acid diester to produce a quaternary phosphonium salt in the second step. On one hand, hydrogen phosphide (PH
3
) and higher phophines, including primary phosphines, secondary phosphines, and tertiary phosphines, after neutralization with protonic compound, become sufficiently reactive and can be alkylated by carbonic acid diester to form quaternary phosphonium cations. On the other hand, as an anion-exchange procedure is completely avoided, the process not only gives quaternary phosphonium salts of high purity, but also gives people freedom to design the cation and the anion of a quaternary phosphonium salt synchronously by choosing a preferred phosphine and a protonic compound that can supply a desired anion.
A Tandem “On-Palladium” Heck-Jeffery Amination Route Toward the Synthesis of Functionalized Indole-2-carboxylates
作者:James McNulty、Kunal Keskar
DOI:10.1002/ejoc.201101072
日期:2011.12
A direct synthesis of functionalizedindole-2-carboxylates involving a PdII-catalyzed annulation of ortho-iodoanilines onto a vinyl ether is described. The reaction mechanism is shown to be distinct from a stepwise Heck, intramolecular amination pathway, likely involving a tandem “on-palladium” Heck–Jefferyamination process incorporating a novel intramolecular amination step.
Methods and compositions providing enhanced chemiluminescence from
申请人:Lumigen, Inc.
公开号:US05451347A1
公开(公告)日:1995-09-19
A dicationic surfactant for enhancing the chemiluminescence of chemiluminescent compounds particularly dioxetanes which are triggerable is described. The surfactant has the formula X.sup.- (R.sub.1).sub.3 A.sup.+ CH.sub.2 --Link--CH.sub.2 A.sup.+ (R.sub.2).sub.3 X.sup.- wherein A is selected from the group consisting of phosphorus and nitrogen atoms separately or together, wherein X is an anionic counterion and R.sub.1 and R.sub.2 are selected from the group consisting of unsubstituted and substituted alkyl and aralkyl groups containing 1 to 20 carbon atoms and R.sub.1 and R.sub.2 can be the same or different, and wherein Link is a carbon chain group selected from the group consisting of dialkylenearyl, aryl, alkylene, alkenylene and alkynylene groups containing 4 to 20 carbon atoms. The surfactants are particularly useful in Western and Southern blot assays.
Optically Active 4,4-Di-Substituted Oxazolidine Derivative and Method for Producing Same
申请人:Onoda Toshihiko
公开号:US20080108828A1
公开(公告)日:2008-05-08
An optically active 4,4-di-substituted oxazolidine compound having the formula (I)
wherein R
1
represents a substituted C
1
-C
3
alkyl group, a substituted C
2
-C
3
alkenyl group, a formyl group, a hydroxymethyl group, a group of the formula COOR, a halogenated methyl group, a phosphonium methyl group; R represents a C
1
-C
6
alkyl group, a C
2
-C
6
alkenyl group, a phenyl group or a benzyl group; R
2
represents a C
1
-C
6
alkyl group, a C
3
-C
10
cycloalkyl group, or the like or a phenyl group; R
3
represents a C
2
-C
6
alkanoyl group, a C
1
-C
6
alkyloxycarbonyl group, a benzoyl group, a phenyloxycarbonyl group or a benzyloxycarbonyl group and R
4
represents a C
1
-C
6
alkyl group or a C
2
-C
6
alkenyl group.