Amyl acetate hydrolysis

Isotopic substitution. A classic example is the demonstration by Polanyi and Szabo (37) of acyl-oxygen fission in the alkaline hydrolysis of -amyl acetate. An ester could undergo cleavage at two locations, as indicated in 3. 

For the saponification of esters, evidence similar to that on p. 227 indicates that the reaction usually proceeds with acyl-oxygen fission. The most self-contained proof again has been obtained by the use of Ols. The alkaline hydrolysis of amyl acetate in water containing this isotope showed that the amyl alcohol which was formed contained only O16 18... 

Polanyi and Szabo by usihg isotopic oxygen in the alkaline hydrolysis of amyl acetate showed that the acyl oxygen bond was broken. 

Esters. Esters are, in general, fairly readily hydrolysed in the body to give the corresponding alcohol and acid anion. They thus show the generic properties of irritation and effects on the CNS, together with any systemic effects associated with the products of hydrolysis. Such effects are usually associated with the alcohol. For example, ethyl acetate (OES 400 ppm 8h TWA) shows little in the way of specific toxicity whereas amyl acetate can give rise to anaemia and liver effects similar to those produced by amyl alcohol. 

Poly(methyl methacrylate) prepared by free radical polymerization is amorphous and is therefore soluble in solvents of similar solubility parameter. Effective solvents include aromatic hydrocarbons such as benzene and toluene chlorinated hydrocarbons such as chloroform and ethylene dichloride and esters such as ethyl acetate and amyl acetate. Some organic materials, although not solvents for the polymer, cause crazing and cracking, e.g., aliphatic alcohols and amines. Poly(methyl methacrylate) has very good resistance to attack by water, alkalis, aqueous inorganic salts and most dilute acids. Some dilute acids such as hydrocyanic and hydrofluoric acids, however, do attack the polymer, as do concentrated oxidizing acids. Poly(methyl methacrylate) has much better resistance to hydrolysis than poly(methyl acrylate), probably by virtue of the... 

A third alkaloid contained sulfur (a rare feature in higher plant nitrogen heterocycles) and was shown to be 4-methylthiocanthin-6-one (XIV) (9). Hydrolysis with amyl alcoholic alkali gave methyl mercaptan and the phenol XV which, upon permanganate oxidation, furnished /3-carboline-l-carboxylic acid. The phenol did not form a quinoxaline with o-phenylenediamine, and its acetate in moist ethereal diazomethane... 

An analogous change is involved in the conversion of ketones possess ing a methylenic hydrogen atom as in methyl n-amyl ketone, propiophenone, and cyclohexanone. Btomination of the enol acetates with subsequent hydrolysis in methanol gives a-bromo ketones in 46-90% yields. ... 

Sulfuric or phosphoricacids are used for the ketonic hydrolysis, as in the preparation of methyl n-amyl ketone. Also, the hydrolysis is brought about by boiling with acetic-sulfuric acid mixture, hot 5% potassium hydroxide solution, or hydriodic acid if the hydrolysis is especially difficult. Benzyl ace tone, QH, CHjCHjCOCH, is formed by hydrolysis of the corresponding /8-keto ester with water at 150-250° and 200 atm. Diaikylated /S-keto esters are stable to this treatment therefore, a single ketone can be obtained from a mixture of mono- and di-alkylated /3-keto esters. ... 

The benzylidene acetal is cleaved by acidic hydrolysis (e.g., 0.01 N H2SO4, 100°C, 3h, 92% yield 80% AcOH, 25°C, f,/2 for uridine - 60b h, conditions that do not cleave a methylenedioxy group. The rate of acid-catalyzed hydrolysis of benzylidene acetals increases as the size of the substituent R increases. The second-order rate constant k, on going from R — Me to R — f-amyl, increases about 100-fold, indicating that steric effects play a large role in determining hydrolysis rates. ... 

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