84508-61-2

Upstream product

• 536-38-9 4-chlorobenzoylmethyl bromide 
• 149-73-5 trimethyl orthoformate 
• 67-56-1 methanol 
• 99-91-2 para-chloroacetophenone 
• 104-88-1 4-chlorobenzaldehyde 

Downstream Products

• 52449-43-1 (4-chloro-phenyl)-acetic acid methyl ester 

Relevant academic research and scientific papers

One-step conversion of acetophenones to α-haloacetophenone dimethyl acetals using DCDMH/DBDMH and molecular sieve in methanol

Using DCDMH/DBDMH as N-halo reagent, piperidine as catalyst, and 4-A molecular sieve as water-removing agent, α-haloacetophenone dimethyl acetals were directly obtained from the solvent of methanol. As to the substrates with electronwithdrawing groups, the conversions were 80-100%. Copyright Taylor & Francis Group, LLC.

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.

EQUILIBRIA INVOLVING HEMIKETAL AND KETAL FORMATION FROM 2-HALOGENOACETOPHENONES

1H-, 13C-NMR, GC measurements and some preparative work have been made to determine the hemiketal and ketal concentrations in mixtures of alcohols and 2-halogenoacetophenones.Equilibrium values for these products, as well as the time required to reach the equilibrium in the absence of acid, were found to be surprisingly high.Comparisons of the values with those of chloroacetone have also been accomplished.

Esters of α-Arylalkanoic Acids from 'Masked' α-Halogenoalkyl Aryl Ketones and Silver Salts: Synthetic, Kinetic, and Mechanistic Aspects

A method for the synthesis of alkyl esters of α-arylalkanoic acids is given based on silver-ion-assisted (AgBF4, AgOSO2CF3, AgSbF6, AgNO3) solvolysis of alkyl acetals of primary and secondary α-halogenoalkyl aryl ketones (Hal = I, Br, Cl) in an alcoholic medium (methanol, ethanol).The reaction is quite selective and alkyl esters are the only reaction products; ethers, which are possible substitution products, are not found.The importance of masking the carbonyl as the acetal is emphasised.The reaction is found to be first-order in AgBF4 and in the primary α-halogeno acetal.A three-point Hammett correlation (ρ = -3.29) between ?+ and the rate constants suggests a large cationic contribution as well as strong aryl participation in the transition state.The role payed by the oxygen of the acetal group in the specificity of the reaction is discussed in comparison with the reactivity of analogous compounds with saturated skeletons and of α-halogenoalkyl aryl ketones.