Saponification acetic acid esters

This arises, because water accelerates the direct saponification reaction between the EVA and the alkali catalyst. Moreover, water also accelerates the reaction between an acetic acid ester formed as a byproduct in the transesterification and the alkali catalyst. 

The acetic acid ester of cellulose is produced by acetylation at 50 "C with acetic anhydride with sulfuric acid added as catalyst in glacial acetic acid or CH2CI2 solution. In contrast to nitration, a direct partial acetyliza-tion is impossible because under milder conditions only a mixture of fully acetylated and nonacetylated molecules is obtained. Therefore partially acetylated products must be produced by saponification of the primarily... 

The PVA process is highly capital-iatensive, as separate faciUties are required for the production of poly(viayl acetate), its saponification to PVA, the recovery of unreacted monomer, and the production of acetic acid from the ester formed during alcoholysis. Capital costs are far in excess of those associated with the traditional production of other vinyl resins. 

By reduction with zinc-dust and acetic acid it yields the acetic ester of perillic alcohol, from which the alcohol itself is separated by saponification. 

Butylcyclohexanol has been prepared from />-/-butylphenol by reduction under a variety of conditions.3 4 Winstein and Holness5 prepared the pure trans alcohol from the commercial alcohol by repeated crystallization of the acid phthalate followed by saponification of the pure trans ester. Eliel and Ro 6 obtained 4-f-butylcyclohexanol containing 91% of the trans isomer by lithium aluminum hydride reduction of the ketone. Iliickel and Kurz 7 reduced />-/-butylphenol with platinum oxide in acetic acid and then separated the isomers by column chromatography. 

The thiazole ring has been found to be an occasional surrogate for a phenyl ring in certain antiinflammatory agents. Note that the side chain is restricted to a simple acetic acid in this series. Reaction of p-chloro-2-mercaptoacetophenone (198) with ethyl cyanoacetate in the presence of base affords thiazole 200. The reaction may involve an adduct such as the iminothioether 199 as an intermediate. Saponification of the ester moiety of 200 then gives the antiinflammatory agent fenclozic acid... 

Poly(vinyl alcohol) has the structure 10.67. Poly(vinyl acetate) is the fully esterified derivative of polyfvinyl alcohol), in which the -OH groups are replaced by -OCOCH3 groups. As indicated in Table 10.5, commercial polyvinyl sizes are effectively copolymers of polyfvinyl acetate) and polyfvinyl alcohol) that vary in the degree of saponification of the ester groups. These products may comprise 100% of either polymer, or combinations of the two monomers in any proportions. Crotonic acid (2-butenoic acid), widely used in the preparation of resins, may also be a component. This compound exhibits cis-trans isomerism (Scheme 10.17). The solid trans form is produced readily by catalysed rearrangement of the liquid cis isomer. 

The second synthetic approach to oidiolactone C (61) is summarized in Scheme 20. This route also commences with the ozonolysis of trans-communic acid 180. Now, when this compound was exposed to ozone in excess, keto aldehyde 187 was obtained in 76% yield. The key step in this approach was the y-lactone closure via chemoselective reduction of the lactone moiety on compound 189 through a SN2 mechanism. Compound 189 could be prepared by saponification of the corresponding methyl ester with sodium propanethiolate. Once the primary alcohol is oxidized, the completion of the synthesis of key lactone 103 only requires the allylic oxidation of the C-17 methyl with concomitant closure of the 8-lactone. This conversion was achieved with Se02 in refluxing acetic acid to give 103 in 51% yield. 

Reaction of (2-aminophenyl)-(4-bromophenyl)-methanone with methylsulfanylacetic acid ethyl ester and tert-butyl hypochlorite gives a corresponding sulfonium salt. This salt was transformed to initially to the betaine. Electrocyclic rearrangement of that transient intermediate leads, after rearomatization, to the homoanthranilic acid. Internal ester-amine interchange leads then to 4-bromophenyl-(3-(methylthio)indolin-7-yl)methanone. The thiomethyl group is then removed with Raney nickel to give 4-bromophenyl-(indolin-7-yl)methanone. Saponification of this intermediate affords the (2-amino-3-(4-bromobenzoyl)-phenyl)-acetic acid (Bromfenac). 

Dipropyl acetic acid or valproic acid may be prepared the next way. Propylbromide is mixed with cyanacetic acid in the presence of sodium ethylate, made from absolute ethanol and sodium. By that prepared a,a-dipropylcyanacetic acid ethyl ester is saponified with equimolecular amounts of NaOH to give dipropylacetonitril. The desired dipropylacetic acid is produced by saponification of dipropylacetonitryl with aquatic NaOH. It is colorless liquid. BP 219°-220°C. 

Indanyl)-phenol 16 was obtained by reacting p-methoxy-phenyl-acetic acid ethyl ester with benzylchloride to form a-benzyl-p-methoxyphenyl ethyl acetate, saponification into the acid, conversion of the acid with thionylchloride into the chloride, cyclization to 2-p-methoxy-phenyl-l-indanone, NaBH4 reduction to 2-p-methoxyphenyl-l-indanole, dehydration with p-toluene-sulphonic acid in toluene to 2-p-methoxyphenyl-indene, catalytic hydrogenation to 2-p-methoxyphenyl-indene, and treating the ether with HBr [Eq. (5)]. 

Ethyl linoleate is prepared by debromination of the tetra-bromide by action of zinc, or nascent hydrogen from zinc and glacial acetic acid 3 by zinc and alcoholic-hydrochloric acid 2, 4 and by zinc and alcoholic-sulfuric acid.5 The pure acid can be obtained by saponification of the ester, and directly by action of zinc and pyridine (quinoline, aniline, piperidine) on tetrabromo-stearic acid.6... 

The search for endothelin antagonists as potential compounds for treating cardiovascular disease was noted in Chapter 5 (see atrasentan). A composed with a considerably simpler structure incorporates a pyrimidine ring in the side chain. Condensation of benzophenone (94) with ethyl chloro-acetate and sodium methoxide initially proceeds to addition of the enolate from the acetate to the benzophenone carbonyl. The aUcoxide anion on the first-formed quaternary carbon then displaces chlorine on the acetate to leave behind the oxirane in the observed product (95). Methanolysis of the epoxide in the product in the presence of boron triflor-ide leads to the ether-alcohol (96). Reaction of this with the pyrimidine (97) in the presence of base leads to displacement of the methanesulfonyl group by the aUcoxide from 96. Saponification of the ester group in that product gives the corresponding acid, ambrisentan (98). " ... 

Norbornanone is generally prepared from the Diels-Alder adduct of cyclopentadiene and vinyl acetate by hydrogenation, saponification, and oxidation with chromic acid in acetic acid solution. The present procedure, which gives higher over-all yields in fewer steps, makes use of the superior solvent, acetone, for mild chromic acid oxidations and of the observation that formate esters of secondary alcohols can be oxidized directly to ketones. ... 

The sodium or potassium salt of palmitic acid, or of stearic acid or the mixed salts of several acids obtained from ordinary fats, is the common substance known as soap. This particular reaction of hydrolysis, is, therefore, known, also, as a reaction of saponification (soap formation). Strictly speaking the reaction of saponification applies only to the alkaline hydrolysis of fats, i,e., of glycerol esters, but, as the hydrolysis of other esters is a reaction of exactly the same character, the term is used to apply equally to the hydrolysis of any ester in presence of an alkali. In the case of the lower alcohol and lower acid esters, e.g., ethyl acetate, the salt formed is not a soap but is a crystalline salt, sodium acetate. 

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