38424-23-6

Upstream product

• 18869-29-9 (E)-4,4'-dimethylstilbene 
• 67-56-1 methanol 
• 2510-76-1 (Z)-4,4'-dimethylstilbene 
• 64-19-7 acetic acid 
• 1588-49-4 4,4'-dimethylstilbene 
• 2378-86-1 4-methylbenzyltriphenylphosphonium bromide 
• 603-35-0 triphenylphosphine 
• 104-82-5 4-Methylbenzyl chloride 
• 1530-37-6 (4-methylbenzyl)triphenylphosphonium chloride 

Downstream Products

• 3457-48-5 1,2-di(4-methylphenyl)-1,2-ethanedione 
• 2789-88-0 1,2-bis(4-methylphenyl)acetylene 
• 5140-98-7 4,4′-bis(bromomethyl)tolan 
• 1374989-07-7 (E)-1,2-di(4-methylphenyl)ethenylboronic acid 
• 1374988-79-0 (R)-3-[5-methyl-2-((E)-2-(4-methylphenyl)ethenyl)phenyl]cyclohexanone 
• 18869-29-9 (E)-4,4'-dimethylstilbene 

Relevant academic research and scientific papers

Asymmetric conjugate addition of cis-2-arylethenylboronic acids catalyzed by chiral diene/rhodium complexes: 1,4-rhodium shift from alkenylrhodium to arylrhodium intermediates

The reaction of (E)-1,2-diphenylethenylboronic acid 1 with 2-cyclohexenone in the presence of a chiral diene/rhodium catalyst (5 mol %) gave 3-[2-((E)-2-phenylethenyl)phenyl]cyclohexanone in 99% yield with 98.7% ee; the catalytic cycle involves a 1,4-rhodium shift from a 2-phenylethenylrhodium to an ortho-alkenylphenylrhodium intermediate. In the reaction of 1 with (E)-1-phenyl-2-buten-1-one, either the tandem 1,4-shift/arylation product or the direct alkenylation product is formed selectively by an appropriate choice of chiral diene ligand.

Solvolytic stereoselective debromination of vic-dibromides with HMPA

A simple and efficient procedure for the debromination of vic-dibromides has been reported with hexamethylphosphoric triamide at 155-160°C under a nitrogen atmosphere without the aid of any reagent.

Stereoselective halogenations of alkenes and alkynes in ionic liquids

(matrix presented) Room-temperature ionic liquids, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium bromide, and 1-butyl-3-methylimidazolium chloride, are used as "green" recyclabl

Equilibria and UV-spectral characteristics of BrCl, BrCl2-, and Br2Cl- species in 1,2-dichloroethane - Stereoselectivity and kinetics of the electrophilic addition of these species to alkenes

UV/Vis spectrophotometric measurements have been used to determine the equilibrium constants and the absorption spectra of Bu4N+Br2Cl- and Bu4N+BrCl2- species in 1,2-dichloroethane (DCE) at 25°C. The formation constants and the absorption spectra of BrCl from Br2 and Cl2 and of Bu4N+Cl3- species from Bu4N+Cl- and Cl2 were also determined in this solvent at 25°C. The kinetics and the products of bromochlorination of several aryl-substituted olefins with BrCl, with Br2 in the presence of an excess of Bu4N+Cl- (Br2/Cl-), and with BrCl in the presence of an excess of Bu4N+Cl- (BrCl/Cl-) were investigated in DCE at different temperatures. The kinetics and product distribution data for the reactions with Br2/Cl- or BrCl/Cl- are interpreted on the basis of a mechanism involving a product- and rate-determining nucleophilic attack by chloride on the olefin-halogen (Br2 or BrCl) π complex. The data relating to the electrophilic addition of BrCl are interpreted in terms of the initial formation of a 1:1 olefin-BrCl π complex, the ionization of which, catalyzed by a second halogen molecule, gives a bromonium (or β-bromocarbenium) BrCl2- ion pair able to collapse to the corresponding bromochloro adducts. A significant proportion of the ion pair intermediates may, however, actually be present as bromonium (or β-bromocarbenium) Br2Cl- and Br3- ion pairs, and the collapse of these should be responsible for the formation of the dibromides in BrCl addition.

Preassociation, free-ion, and ion-pair pathways in the electrophilic bromination of substituted cis- and trans-stilbenes in protic solvents

Rates and products of electrophilic bromination of ring-substituted cis- and trans-stilbenes have been investigated in acetic acid, trifluoroethanol, ethanol, methanol, and water-methanol mixtures. The mY(Br) relationships (linear for nucleophilic solvent

Formation of Bromocarbenium Bromide Ion Pairs in the Electrophilic Bromination of Highly Reactive Olefins in Chlorinated Aprotic Solvents

The kinetics and the products of bromination of several substituted stilbenes with tetrabutylammonium tribromide (TBAT) have been investigated in aprotic solvents at different temperatures. Stilbenes bearing electron-withdrawing or moderately electron-donating substituents gave stereospecifically the anti addition products. The reactions followed a second-order rate law, and an inverse kinetic isotope effect (KIE), kH/kD = 0.85(0.05), was found for the bromination of cis-stilbene. The reactions of cis- and trans-4,4-dimethoxystilbenes yielded mixtures of meso and d,l dibromides both in chloroform and 1,2-dichloroethane. The rate constants (kBr3-) measured for the latter olefins deviated considerably from the Hammett correlations, and added bromide had a significant effect on the rates. The reactions of these activated stilbenes with molecular Br2, carried out at low Br2 concentration, followed a mixed second/third-order rate law. The kinetic and product distribution data for the reaction, with TBAT, of stilbenes bearing electron-withdrawing or moderately electron-donating substituents are interpreted on the basis of the known mechanism involving a product-and rate-determining nucleophilic attack by bromide on the olefin-Br2 π-complex. The data related to the bromination of the more activated methoxystilbenes are rationalized considering that, for these olefins, even in aprotic solvents, the ionization of the initially formed 1:1 π-complex to a bromocarbenium bromide ion pair can compete both with the formation of a bromonium-tribromide ion pair and with the nucleophilic attack by Br-. For this second-order process (first order in Br2), the kinetic constants and the activation parameters have been measured in chloroform and 1,2-dichloroethane and the activation parameters have been compared with those related to the third-order Br2 addition and to the reaction with TBAT.

Synthesis, molecular modeling, and K+ channel-blocking activity of dequalinium analogues having semirigid linkers

Dequalinium [1,1'-(decane-l,10-diyl)bis(2-methyl-4-aminoquinolinium)] is an effective blocker of the small conductance Ca2+activated K+ channel. It has been shown that the number of methylene groups in the alkyl chain linking the two quinolinium rings of this type of molecule is not critical for activity. To further investigate the role of the linker, analogues of dequalinium have been synthesized, in which the alkyl chain has been replaced by CH2XCH2 where X is a rigid or semirigid group containing aromatic rings. The compounds have been tested for blockade of the slow after- hyperpolarization on rat sympathetic neurons. The most potent compounds have X = phenanthryl, fluorenyl, cis-stilbene, and C6H4(CH2)(n)C6H4 where n = 0-4. The conformational preferences of the compounds were investigated using the XED/COSMIC molecular modeling system. Although there is some dependence of the potency of the analogue on the conformational properties of the linker (X), overall, X groups having substantial structural differences are tolerated. It seems that X provides a support for the two quinolinium groups and does not interact with the channel directly. The intramolecular separation between the quinolinium rings, which is provided by rigid groups X, is not critical for activity; this may be attributed to the residual conformational mobility of the heterocycles and to the extensive delocalization of the positive charge. These two factors may permit favorable contacts between the quinolinium groups and the channel over a range of intramolecular separations.