33604-54-5

Upstream product

• 100-42-5 styrene 
• 67-56-1 methanol 
• 70-11-1 α-bromoacetophenone 
• 98-85-1 1-Phenylethanol 
• 100-52-7 benzaldehyde 
• 98-86-2 acetophenone 
• 149-73-5 trimethyl orthoformate 

Downstream Products

• 151668-20-1 2-bromomethyl-4,7-dihydro-2-phenyl-1,3-dioxepin 
• 101-41-7 benzeneacetic acid methyl ester 
• 2425-28-7 2-Bromo-1-phenylethanol 
• 64342-39-8 1-nitrato-1-phenyl-2-bromoethane 
• 70-11-1 α-bromoacetophenone 
• 4747-13-1 α-methoxystyrene 
• 5635-16-5 3,4-diphenyl-2(5H)-furanone 
• 135312-64-0 1-(1-bromo-2-methoxypent-4-en-2-yl)benzene 
• 4469-33-4 2-Methyl-2-phenyl-4,7-dihydro-1,3-dioxepin 

Relevant academic research and scientific papers

General Method for the Preparation of Electron-Deficient Imidazo[1,2-a]pyridines and Related Heterocycles

A new annulation method for the preparation of the imidazo[1,2-a]pyridine ring system under mild conditions is presented. Treatment of a 2-aminopyridine with a dimethylketal tosylate in acetonitrile at elevated temperature (80-140°C) in the presence of catalytic Sc(OTf)3 provides the imidazo[1,2-a]pyridine product in good yield. The annulation method is broadly applicable to electron-poor 2-aminopyridines and displays a complementary profile to the classic preparation of the imidazo[1,2-a]pyridine ring system by reaction of a bromoketone with electron-rich and -neutral substrates. The scope of the process and mechanistic considerations are discussed.

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.

Unusual carbon-carbon bond formations between allylboronates and acetals or ketals catalyzed by a peculiar indium(I) lewis acid

InIOTf has been uncovered as an effective Lewis acid catalyst for unprecedented nucleophilic substitution of acetals or ketals with allylboronates. A transmetalative SN1 mechanism is proposed in which a single InI center acts as a dual catalyst to activate both reagents sequentially. Contrary to the classic γ-selectivity of allylsilanes (Hosomi-Sakurai reaction), this InI-catalyzed borono variant displays distinct α-selectivity. Substrate scope and functional group tolerance proved to be excellent.

Oxidation of secondary alcohols with phenyltrimethylammonium tribromide in the presence of a catalytic amount of antimony(III) bromide or copper(II) bromide

The oxidation of alcohols was carried out with phenyltrimethylammonium tribromide in the presence of a catalytic amount of SbBr3 or CuBr2. 1,2-Diols, such as hydrobenzoin, were converted into 1,2-diketones or α-ketols without oxidative cleavage of the glycol C-C bond at room temperature. A variety of secondary alcohols were also oxidized to the corresponding carbonyl compounds in a chemoselective manner.

ANODIC FUNCTIONALIZATION OF OLEFINS IN ALCOHOLS IN THE PRESENCE OF HALIDE SALTS

Electrolysis of conjugated, unbranched arylolefins in the presence of alkali metal halides in alcohols affords 1-aryl-2-bromoketals in 60-90percent yields.Under these conditions, 2-methyl-1-phenylprop-1-ene is converted into 1-bromo-2-methyl-1-phenylprop-1-ene in 80percent yield, and arylolefins with no benzylidene hydrogens give 1-aryl-1-alkoxy-2-bromoalkanes.

THE MUKAIYAMA REACTION OF KETENE BIS(TRIMETHYLSILYL)ACETALS WITH α-HALO ACETALS - A CONVENIENT BUTENOLIDE SYNTHESIS

Ketene bis(trimethylsilyl) acetals were reacted with α-halo acetals giving β-alkoxy-γ-halo acids which were converted to butenolides by reaction with equivalents of base.This constitutes a novel and short butenolide synthesis.

ELAECTROCHEMICAL OXIDATION OF CONJUGATED ARYLOLEFINS TO α-BROMOKETALS

Conjugated arylolefins electrolyzed in alcohols in the presence of alkali metal bromides are transformed into α-bromoketals.

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.

Conversion of Aromatic Ketones into α-Arylalkanoic Acids. Oxidation by Thallium(III) and by Halogens

The mechanism by which thallium (III) nitrate oxidises aromatic ketones to α-arylalkanoic acids has been investigated and the role of additives in the system elucidated.It is found that in the absence of additives an organothallium intermediate, most probably the phenacylthallium species BzCH2Tl(NO3)2, persists and that the key to an efficient rearrangement is the ready conversion of this compound into its acetal.Thallium(III) is shown not to be a unique reagent for the oxidation.Other oxidants capable of acting initially as an electrophile and then as a leaving group are equally effective, provided that formation of an acetal is possible.Iodine-silver nitrate in particular offers considerable advantages as reagent over thallium(III).Higher specificity is achieved, unwanted side-reactions can be avoided, and toxicity problems are eliminated.Bromine may be used instead of iodine, but chlorine proves unsatisfactory as an oxidant.