68240-83-5

Upstream product

• 123-11-5 4-methoxy-benzaldehyde 
• 90875-17-5 Aethoxy-<4-methoxy-phenyl>-methylbromid 
• 64-17-5 ethanol 
• 116664-89-2 (4-methoxyphenyl)-phenylmethyl 4-cyanophenyl ether 
• 441-54-3 4-methoxybenzhydryl trifluoroacetate 
• 6731-11-9 4-methoxybenzhydryl chloride 
• 31558-55-1 4-methoxybenzhydryl phenyl carbonate 
• 940934-41-8 (4-methoxyphenyl)phenylmethyl methyl carbonate 
• 2403-58-9 4-methoxybenzaldehyde diethylacetal 
• 714223-43-5 4-methoxybenzhydryl 3,5-dinitrobenzoate 
• 611-94-9 4-Methoxybenzophenone 

Downstream Products

• 100-17-4 para-methoxynitrobenzene 
• 100-52-7 benzaldehyde 
• 104-92-7 1-bromo-4-methoxy-benzene 

Relevant academic research and scientific papers

Selectivity of stabilized benzhydrylium ions

Methyl carbonates (1-4-OCO2Me) and phenyl carbonates (2-4-OCO2Ph) were subjected to solvolysis in the series of aqueous ethanol, the product ratios were determined and the selectivities (k E/kw) of the correspon

Solvolytic reactivity of pyridinium ions

The leaving group abilities of pyridine, 4-methylpyridine, and 4-chloropyridine in SN1 solvolytic reactions have been determined by analyzing the rate constants of X,Y-substituted benzhydrylpyridinium salts obtained in various solvents. By applying the linear free energy relationship equation, log k = sf (Ef + Nf), the nucleofuge specific parameters of 4-substituted pyridine have been extracted. Because of solvation in the reactant ground state, the reactivity (nucleofugality, Nf) of a given pyridine decreases as the polarity of the solvent increases. High slope parameters (sf > 1) may be due to the spread of the energy levels of the benzhydrylium ion/pyridine pair intermediates in comparison to benzhydrylium ion/chloride pairs (sf ≈ 1). Because of slow heterolysis step of pyridinium salts in various solvents, some are stable under normal conditions.

SN1 reactions with inverse rate profiles

Carbocations may accumulate during solvolysis reactions! The fact that fast ionization followed by slow trapping of the carbocation R+ is a characteristic pattern of many solvolysis reactions requires that the generally accepted energy profiles of these reactions be revised.

Solvent Nucleophilicity

The rates of the reactions of benzhydrylium ions (diarylcarbenium ions) with solvent mixtures of variable composition (water/acetonitrile, methanol/acetonitrile, ethanol/acetonitrile, ethanol/water, and trifluoroethanol/water) have been determined photometrically by conventional UV-vis spectroscopy, stopped-flow methods, and laser flash techniques. It has been shown that the first-order rate constants follow the previously published relationship log k(20°C) = s(N+E), where E is an empirical electrophilicity parameter, N is an empirical nucleophilicity parameter, and s is a nucleophile-specific slope parameter. From plots of log k versus E of the benzhydrylium ions are derived the solvent nucleophilicity parameters s and N, the latter of which are designated as N1 to emphasize that their use in the quoted correlation equation gives rise to first-order rate constants. A linear correlation between N1 and Kevill's solvent nucleophilicity NT based on S-methyldibenzothiophenium ions is reported, which allows one to interconvert the two sets of data. Because the N1 values are directly comparable to the previously reported nucleophilicity parameters N for π-systems (www.cup.uni-muenchen.de/oc/mayr/), the systematic design of Friedel-Crafts reactions with solvolytically generated carbocations becomes possible.

The Reaction between Acyl Halides and Alcohols: Alkyl Halide vs. Ester Formation

In the reaction between an acyl halide and an alcohol the thermodynamically favoured products are the free carboxylic acid and the alkyl halide.The initial reaction is, generally, the formation of an ester and HHal.When the alcohol is very prone to yield an alkyl cation upon protonation by HHal, formed H2O exhibited a superior reactivity and competed successfully with the alcohol for the acyl halide making, therefore, ester formation practically confined to a triggering role.But, in those cases where the cation is less easily formed, ester formation was favoured and, consequently, became the necessary elementary step towards alkyl halide formation.Tis final product, on the other hand, might be extremely slow to form in an SN2 reaction between the protonated ester function and the halide ion.In these instances, therefore, as well as in the cases when a basic solvent competes for the proton of HHal, the ester is the final product.A notable exception of the situation above outlined, is given by α-hydroxy-α-phenylbenzeneacetic acid (2y), which appears to undergo direct chlorine-hydroxyl interchange through a quaternary intermediate (E), in the end collapsing to α-chloro-α-phenyl-benzeneacetic acid (4y).Different systems were compared using CH2Cl2 as a solvent under strictly similar conditions.Some 28 different substrates were tested for reaction with AcCl (1a), whereas the action of eight acyl halides (a) against (RS)-α-methylbenzenemethanol (2n) and α-phenylbenzenemethanol (2p), as well as the effect of five different solvents on the reaction between two alcohols (2p and 2-methyl-2-propanol, 2c) with 1a, were observed.