Ethylene Glycol acetal formation

Reaction of 1,2-dimethylcyclohexene with the ethylene glycol acetal of acrolein in methylene chloride in the presence of 25 mol % of BF3.0Et2 at -78 to -10°C for 2 hours gives a 70% yield of the cycloadduct 1 in a formal 2k + 2% intermolecular cycloaddition. All of the evidence for this and related reactions, however, indicates a stepwise mechanism for the formation of 1. 

Tris (ethylenediamine) cadmium dihydroxide Zinc chloride solvent, cellulose acetate Acetylacetone Benzaldehyde Benzyl acetate Butyl formate Cyclohexanone Cyclopentane Diacetone alcohol Diethyl phthalate Ethylbenzene Ethylene glycol acetate... 

Diethyl tartrate Diisobutyl ketone Dimethyl sebacate Ethoxydiglycol Ethoxyethanol Ethylene glycol acetate Ethyl formate 2-Ethylhexanol 2-Ethylhexyl acetate Ethyl-(S)-lactate... 

The thermodynamics of ethylene glycol diacetate formation from CO/H2 (eq. 9) have been estimated to be more favorable than for the comparable direct glycol route (eq. 10) (14). Nevertheless, at the temperatures necessary to achieve measurable rates of glycol acetate formation (>180 C), reaction is very sensitive to experimental conditions (see Table III) such as (i) the ruthenium cation halogen mole ratio (11), (ii) the nature of the cationic cocatalyst species, and... 

A mixture of ethylene glycol, acetic anhydride, and difluoronitroacetic acid stirred vigorously for 15 min., whereby the temp, rises to 100-110 glycol diacetate. Y ca. 100%.—The catalytic power of the difluoronitroacetic acid stems from the formation of a mixed anhydride, which is a powerful acylating agent. F. e. s. A. V. Fokin, A. A. Skladnev, and V. A. Komarov, X, 33, 3271 (1963) G. A. 60, 3999g. 

Catechol also has two OH groups (like ethylene glycol). So, when treated with a ketone or aldehyde in acidic conditions, catechol can behave much like ethylene glycol, giving formation of a cyclic acetal ... 

The formation of acetals with methanol, ethanol, or ethylene glycol in the presence of an acid catalyst such as hydrogen chloride or ben2enesulfonic acid is straightforward. Sodium bisulfite and hydroxjlamine form adducts with cinnamaldehyde that are used in typical quantitative analysis protocols. 

Hydrogenation of enones in MeOH with Pd/C resulted in acetal formation. When ethylene glycol/THF is used as solvent, the related dioxolane is formed in 86% yield. 

In practice, it s convenient to use 1 equivalent of a diol such as ethylene glycol as the alcohol and to form a cyclic acetal. The mechanism of cyclic acetal formation using ethylene glycol is exactly the same as that using 2 equivalents of methanol or other monoalcohol. The only difference is that both —OH groups are in the same molecule. 

Show all the steps in the acid-catalyzed formation of a cyclic acetal from ethylene glycol and an aldehyde or ketone. 

Besides the above mentioned method of Tomoda [phthalonitrile, nickel(II) acetate, 1,8-diaza-bicyclo[5.4.0]undec-7-ene, pen tan-1-ol], nickel phthalocyanine (PcNi) is prepared from phthalonitrile and nickel(II) acetate in 2-(dimethylamino)ethanol117 or with nickel(II) chloride in quinoline.1 30-1 59-277-278 The formation of PcNi also takes place without solvent137 or with nickel(II) acetate in ethylene glycol.127... 

ETHYLENE GLYCOL ETHYL MERCAPTAN DIMETHYL SULPHIDE ETHYL AMINE DIMETHYL AMIDE MONOETHANOLAMINE ETHYLENEDIAMINE ACRYLONITRILE PROPADIENE METHYL ACETYLENE ACROLEIN ACRYLIC ACID VINYL FORMATE ALLYL CHLORIDE 1 2 3-TRICHLOROPROPANE PROPIONITRILE CYCLOPROPANE PROPYLENE 1 2-DICHLOROPROPANE ACETONE ALLYL ALCOHOL PROPIONALDEHYDE PROPYLENE OXIDE VINYL METHYL ETHER PROPIONIC ACID ETHYL FORMATE METHYL ACETATE PROPYL CHLORIDE ISOPROPYL CHLORIDE PROPANE... 

Figure 5.6 Alcohols, aldehydes, ketones and acids 15, ethylene glycol 16, vinyl alcohol 17, acetaldehyde 18, formaldehyde 19, glyoxal 20, propionaldehyde 21, propionaldehyde 22, acetone 23, ketene 24, formic acid 25, acetic acid 26, methyl formate. (Reproduced from Guillemin et at. 2004 by permission of Elsevier)...

Fahey (16) suggests that intermediate 3 dissociates formaldehyde he finds supportive evidence in the rhodium-based system by observation of minor yields of 1,3-dioxolane, the ethylene glycol trapped acetal of formaldehyde. For reasons to be discussed later, we believe the formation of free formaldehyde is not on the principal reaction pathway. (c) We have also rejected two aspects of the reaction mechanism proposed by Keim, Berger, and Schlupp (15a) (i) the production of formates via alcoholysis of a formyl-cobalt bond, and (ii) the production of ethylene glycol via the cooperation of two cobalt centers. Neither of these proposals accords with the observed kinetic orders and the time invariant ratios of primary products. 

Solutions of Ru3(CO)i2 in carboxylic acids are active catalysts for hydrogenation of carbon monoxide at low pressures (below 340 atm). Methanol is the major product (obtained as its ester), and smaller amounts of ethylene glycol diester are also formed. At 340 atm and 260°C a combined rate to these products of 8.3 x 10 3 turnovers s-1 was observed in acetic acid solvent. Similar rates to methanol are obtainable in other polar solvents, but ethylene glycol is not observed under these conditions except in the presence of carboxylic acids. Studies of this reaction, including infrared measurements under reaction conditions, were carried out to determine the nature of the catalyst and the mechanism of glycol formation. A reaction scheme is proposed in which the function of the carboxylic acid is to assist in converting a coordinated formaldehyde intermediate into a glycol precursor. 

Pressure Dependence Studies. The variation of the product distribution as a function of total pressure for the optimum Ru/Rh/EtaN/HOAc system at 1000 atm and 230°C is illustrated in Figure 2. As found in much previous work this once again highlights the very strong pressure requirement for the formation of C2 products, particularly ethylene glycol esters. In contrast however, the rate of formation of methyl acetate is relatively independent of... 

Aldehyde 82 was extremely reactive and was best isolated as the hydrate 84a. Indeed, recrystallization of the aldehyde 82 from ethanol gave 3-(l-ethoxy-l-hydroxymethyl)fervenulin 84b, while reaction with ethylene glycol gave the cyclic acetal 76a. The reactivity of the aldehyde 82 was exploited by easy Schiff base formation upon reaction with /i-aminobenzoylglutamic acid, a process that was followed by reduction to give the fervenulin-based folic acid analogue 85 <1996JHC949>. 

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