Ethylene glycol acetal formation from

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. 

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... 

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)...

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>. 

Fig. 15. Dependences of ethylene glycol diacetate yield (formation rate) on CO and H2 partial pressures. (Adapted from Ref. 166 with permission. Copyright 1980 American Chemical Society.) Partial pressure of reagent not being varied is 170 atm. Reaction conditions 50 ml acetic acid, 2.35 mmol Ru, 230C C, 2 hr.

Acetalization with ethylene glycol under acidic conditions with azeotropic removal of water is the usual protection method for the carbonyl group. In one case the formation of the acetal of ethylene glycol was reported to be troublesome. In this case conditions reported in the first entry in Table 15 were used.317. Examples for the preparation of cyclobutanone acetals from cyclobutanones are given in Table 15. 

Catalytic systems containing Te02, HBr and AcOH have been used industrially by Oxirane to convert ethylene to ethylene glycol via the formation of mono- and di-acetate (equations 131 and 132).359-361 The overall yield from ethylene to ethylene glycol is more than 90%, making this reaction competitive with respect to the older silver-catalyzed ethylene epoxidation process. 

Some terminal alkenes are oxidized to aldehydes depending on their structure. As described before, acrylonitrile and acrylate are oxidized to acetals of aldehydes in alcohols or ethylene glycol.Selective oxidation of terminal carbons in 4-hydroxy-1-alkenes (18) gave the five-membered hemiacetals (19), which can be converted to y-butyrolactones by PCC oxidation (Scheme 4). Formation of a tricyclic six-membered hemiacetal (62%) from a 5-hydroxy-1-alkene system was used for the synthesis of rosa-ramicin. Formation of aldehydes as a major product from terminal alkenes using (MeCN)2Pd(Cl)(N02) and CuCU in r-butyl alcohol under selected conditions was reported. The vinyl group in the -lactam was oxidized mainly to the aldehyde as shown below (equation 12). ... 

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