73585-53-2

Upstream product

• 67-56-1 methanol 
• 89726-07-8 1-chloro-3-(1-methoxyvinyl)benzene 
• 99-02-5 3'-Chloroacetophenone 
• 149-73-5 trimethyl orthoformate 

Downstream Products

• 99-02-5 3'-Chloroacetophenone 

Relevant academic research and scientific papers

Formation of Acetals and Ketals from Carbonyl Compounds: A New and Highly Efficient Method Inspired by Cationic Palladium

The development of a new, highly efficient, and simple method for masking carbonyl groups as acetals and ketals is described. This methodology relies on the nature of the palladium catalyst to direct the acetalization/ketalization reaction. This new protocol is mild and proceed with a very low catalyst loading at ambient temperatures. The method has been extended to a wide variety of different carbonyl compounds with various steric encumbrances to form the corresponding acetals and ketals in excellent yields.

Kinetics and Mechanism of Acid-catalysed Addition of Methanol to α-Methoxystyrenes

A kinetic study of the complex behaviour of ring-substituted α-methoxystyrenes in acidic (HBr) methanol is reported.The reaction yields the corresponding acetals as the only kinetic products; these are subsequently partly hydrolysed into acetophenones with rates only a little lower than those of their formation.The rate-limiting step for methanol addition corresponds to proton attachement to the double bond, yielding an oxocarbenium ion which is trapped by methanol with a rate constant 10E4 higher than that of ion deprotonation.The rate constants for proton transfer from CH3OH2+ are in the same range of magnitude as those for proton transfer from H3O+ in water.The lyonium ion catalytic constants fit a good Young-Jencks equation with ρn-2.86 and ρr-1.28

Kinetics and Mechanism of the Acid-Catalyzed Bromination of Ring-Substituted Acetophenones in Methanol. Thermodynamics of the Ketone-Acetal-Enol Ether System in Mathanol and Water

The kinetics of HBr-catalyzed bromination of ring-substituted acetophenones in equilibrium with acetals have been studied in methanol containing small amounts of water at very low halogen concentration (ca. 10-6 M).Under these conditions, the rate is zeroth order with respect to the halogen and first order with respect to the CH3OH2+ ion and the overall carbonyl compound concentrations.The relative concentration of acetal at equilibrium (xeq = eq/(eq + eq)) has been varied by increasing the water concentration; the lyonium ion catalytic constant depends linearly on xeq with an xeq = 0 intercept corresponding to bromination via intermediate enol formation and with an xeq = 1 intercept corresponding to bromination via enol ether.In the case of 3-nitroacetophenone (1a), these extrapolated rate constants are identical with those directly measured from the rates for bromination of 1a and of 1a dimethyl acetal, before ketone-acetal equilibration.In most cases, the enol ether path is highly predominant.Substituent effects on the constants associated with the two paths are examined.The rate constants for enol ether formation are combined with rate constants for the reverse process and with acetal formation equilibrium constants to provide acetal-to-enol ether and ketone-to-enol ether equilibrium constants in methanol.Taking into account data of Gibbs free energies of transfer from methanol to water for the different species involved, equilibrium data in water are also deduced.

Ring Substituent Effects on Acetophenone Dimethyl Acetal Formation. 2. Dual-Parameter Treatment of Kinetic Data for Acid-Catalyzed Acetal Formation and Hydrolysis in Methanol Containing Small Amounts of Water

The rates of formation and hydrolysis of para- and meta-substituted acetophenone dimethyl acetals have been measured, by a water-concentration method, in methanol containing HBr and small amounts of water.The rate coefficients for pure anhydrous methanol have been extrapolated .Acid and water-concentration effects are consistent with the usual mechanism for acetal hydrolysis in water, but the rate-limiting step in the hydrolysis direction corresponds to water addition to the hemiacetal-yielding oxocarbenium ion.Substituent effects on both extrapolated rate coefficients fit the Young-Jencks-modified Yukawa-Tsuno equation.The validity of this equation and its usefulness for separating polar and conjugative effects are discussed.