Benzoic 0-ethyl

Toluene.—According to Renard,1 this compound, by electrolytic oxidation in alcoholic-sulphuric acid, forms benzaldehyde and phenose, C6H6(OH)6( ). According to Puls,2 there are produced in the same electrolyte, using a diaphragm and a platinum anode, benzaldehyde, benzoic acid, benzoic ethyl ester, and, as chief product, p-sulphobenzoic acid. Under the same conditions, Merzbacher and Smith3 had obtained a poor yield of benzoic ethyl ester. 

Benzoic Esters.—Tafel and Friedrichs,2 by conducting the electrolysis in alcoholic-aqueous sulpnuric acid at lead or mercury cathodes, obtained methyl benzyl ether and the ethyl benzyl ether from benzoic methyl and benzoic ethyl esters respectively. Mettler,3 by a similar arrangement, obtained chiefly benzyl alcohol and some benzyl methyl ether from benzoic methyl ester. 

Benzoic Ethyl acetate 1-Borneol Acetophenone Acetoin... 

The same applies to esters where names of the type benzoic ethyl ester (in German Benzoesaureathylester ) are to be preferred to names of the type ethyl benzoate, when the acid has a long name. 

An equimolar amount of BFg-etherate added to benzoic ethyl carbonic anhydride ethyl benzoate. Y excellent. F. e. s. T. B. Windholz, J. Org. Chem. 25, 1703 (1960). 

Methyl, ethyl, n-propyl, isopropyl, n-hutyl, benzyl, cyclohexyl esters of formic, acetic, oxalic, succinic, tartaric, citric, benzoic, salicylic (and other substituted benzoic acids), phthalic and cinnamic acids phenyl esters of acetic, benzoic and salicylic acids. 

Ethyl benzoate sulphuric acid as a catalyst). Use 30 g. of benzoic acid, 115 g. (146 ml.) of absolute ethyl alcohol and 5 g. (2 7 ml.) of concentrated sulphuric acid. Reflux the mixture for 4 hours and work up as for Methyl Benzoate. The yield of ethyl benzoate, b.p. 212-214°, is 32 g. 

To obtain crystalline perbenzoic acid, dry the moist chloroform solution with a little anhydrous sodium or magnesium sulphate for an hour, filter, and wash the desiccant with a little dry chloroform. Remove the chloroform under reduced pressure at the ordinary temperature whilst carbon dioxide is introduced through a capillary tube. Dry the white or pale yellow residue for several hours at 30-35° under 10 mm. pressure. The yield of crystalline perbenzoic acid, m.p. about 42°, which is contaminated with a little benzoic acid, is 22 g. It is moderately stable when kept in the dark in a cold place it is very soluble in chloroform, ethyl acetate and ether, but only shghtly soluble in cold water and in cold hght petroleum. 

The benzoic acid derivative 457 is formed by the carbonylation of iodoben-zene in aqueous DMF (1 1) without using a phosphine ligand at room temperature and 1 atm[311]. As optimum conditions for the technical synthesis of the anthranilic acid derivative 458, it has been found that A-acetyl protection, which has a chelating effect, is important[312]. Phase-transfer catalysis is combined with the Pd-catalyzed carbonylation of halides[3l3]. Carbonylation of 1,1-dibromoalkenes in the presence of a phase-transfer catalyst gives the gem-inal dicarboxylic acid 459. Use of a polar solvent is important[314]. Interestingly, addition of trimethylsilyl chloride (2 equiv.) increased yield of the lactone 460 remarkabiy[3l5]. Formate esters as a CO source and NaOR are used for the carbonylation of aryl iodides under a nitrogen atmosphere without using CO[316]. Chlorobenzene coordinated by Cr(CO)j is carbonylated with ethyl formate[3l7]. 

The two OH groups m the tetrahedral intermediate are equivalent and so either the labeled or the unlabeled one can be lost when the tetrahedral intermediate reverts to ethyl benzoate Both are retained when the tetrahedral intermediate goes on to form benzoic acid... 

Propiophenone. Propiophenone [93-55-0] (ethyl phenyl ketone) is a colorless Hquid with a flowery odor. It can be prepared by the Friedel-Crafts reaction of benzene and propionyl chloride in the presence of aluminum chloride (346), or by the catalytic reaction of benzoic acid and propionic acid in the presence of water (347). Propiophenone is commercially available (348), and is sold in Japan at 2700 Y/kg (349). It is used in the production of ephedrine, as a fragrance enhancer, and as a polymerization sensitizer. 

Perfumes, Flavors, Cosmetics, and Soap. Many naturally occurring esters in essential oils and some synthetic esters are important fragrance and flavor compounds (61,62). They are used in perfumes, flavors, cosmetics, soaps, detergents, and air fresheners. Benzyl, butyl, ethyl, methyl, and phenyl esters of benzoic acid are used as flavors, perfumes, and food preservatives. Glyceryl 4-aminobenzoate [136-44-7] and 2-ethyUiexyl 4-dimethylaminobenzoate [21245-02-3] are used in cosmetic sunscreen preparations. Alkyl esters of 4-hydroxybenzoic acid, called parabens, have been used under various names for fungus infections of the skin, and as preservatives in lotions and creams (101). Soap and cosmetic fragrances use large amounts of amyl and benzyl saHcylate. Benzyl saHcylate [118-58-1] is also used in deodorant sprays. 2-Ethylhexyl saHcylate [118-60-5] and 2-ethylhexyl 4-methoxycinnamate [5466-77-3] are used in sunscreen formulations (102). 

The influence of NH., and CO, on the chromatographic behaviour of benzoic acid and its derivatives (o-, m-, p-hydroxybenzoic, nitrobenzoic, aminobenzoic, chlorobenzoic acids) was studied. The work was carried out by means of upgoing TLC on Sorbfil plates. Isopropanol- and ethyl acetate-containing water-organic eluents were used as mobile phases in the absence or presence of gaseous modifiers in the MP. The novel modification of TLC has been found to separate benzoic acids with different values of their dissociation constants more effectively than water-organic mobile phases. 

Ethyl 4,5-Dlbenzamldopent-4-enoate (2) Ethyl 3-lmidazol-4(5)-ylpropanoale 1 (9.2 g, 54 mmol) In ElOAc (140 mL) was treated with benzoyl chloride (15 7 g, 112 mmol) In ElOAc (40 mL) and 1M NaHCOa (380 mL) added simultaneously In 1 h under Ice-cooling. The reaction mixture was stirred for 1 h, then a further portion of benzoyl chloride (IS 7 g, 112 mmol) in ElOAc) and iM NaHCOa (280 mL) was added m the same manner, followed by an additional portion o( 1M NaHCOa (200 mL) The reaction mixture was stirred for 24 h, then the organic layer was separated, concentrated, and the residue dissolved in THF (300 mL) The THF solution was stirred with 10% NaHCOa (600 mL) for 24 h to decompose any N-lormyl intermediate and to remove benzoic acxl Extraction with EtOAc, drying (Na2S04), solvent evaporation and recrystallization of the residue from EtOAc hexane afforded 16 24 g of 2 (84%), mp 128-129°C... 

Propionic acid [79-09-4] M 74.1, b 141 , d 0.992, n 1.3865, n25 1.3843, pK 5-6.8 (Ho scale, aq H2SO4), pK2 4.88. Dried with Na2S04 or by fractional distn, then redistd after refluxing with a few crystals of KMn04. An alternative purification uses the conversion to the ethyl ester, fractional distn and hydrolysis. [Bradbury J Am Chem Soc 74 2709 1952.] Propionic acid can also be heated for 0.5h with an amount of benzoic anhydride equivalent to the amount of water present (in the presence of Cr03 as catalyst), followed by fractional distn. [Cham and Israel 7 C/iem 5oc 96 I960.]... 

Fig. 4.2. Conelation of acid dissociation constants of benzoic acids with rates of alkaline hydrolysis of ethyl benzoates. [From L. P. Hammett, J. Am. Chem. Soc. 59 96 (1937).]...

In a typical Knof procedure, 3jS-hydroxyandrost-5-en-17-one acetate is epoxidized with perbenzoic acid (or m-chloroperbenzoic acid ) to a mixture of 5a,6a- and 5)5,6)5-epoxides (75) in 99 % yield. Subsequent oxidation with aqueous chromium trioxide in methyl ethyl ketone affords the 5a-hydroxy-6-ketone (76) in 89% yield. Baeyer-Villiger oxidation of the hydroxy ketone (76) with perbenzoic acid (or w-chloroperbenzoic acid ) gives keto acid (77) in 96% yield as a complex with benzoic acid. The benzoic acid can be removed by sublimation or, more conveniently, by treating the complex with benzoyl chloride and pyridine to give the easily isolated )5-lactone (70) in 40% yield. As described in section III-A, pyrolysis of j5-lactone (70) affords A -B-norsteroid (71). Knof used this reaction sequence to prepare 3)5-hydroxy-B-norandrost-5-en-17-one acetate, B-noran-... 

Ethyl Acetoacetate. -The e. planation of the manner in which this substance is produced has been given in the account of the preparation. The result was anived at, not by the iscila-tion of the intermediate compound formed by the union of ethyl acetate with sodium ethylate, but by analogy with the behaviour of benzoic methyl ester with sodium benzylate, which gave the same additive product as that obtained by combining benzoic benzyl ester with sodium methylate, showing that such combinations could occur,... 

Alcohols.—It may be a liquid alcohol (methyl, ethyl, propyl, etc., glycerol, benzyl) or a solution of it in nater. In the former case its boiling-point will have already been determined. Itttiay be fiirthei identified (1) by converting it into the benzoic... 

Contains Halogen.—Halogen compounds may be n/ly/em aryl or add haUdc tQ ha/oyru aethylene bromide, btomoben/ene, benzoyl cbloiide, oi rhloio-benzoic acid). 

The rates of alkaline hydrolysis of ethyl benzoate, ethyl 2-thenoate, and 3-thenoate are very similar. Also, the acid constants of benzoic acid (pAfl = 4.20) and 3-thenoic acid (pKa " 4.08) are of the same magnitude, whereas 2-thenoic acid (piCa = 3.49) is stronger. 

The benzoic acid moiety common to many of the benzamides is prepared in straightforward manner from the methyl ether of p-aminosalicylic acid 141. Acylation on nitrogen (142) followed by chlorination gives intermediate 143 benzoic acid 144 is then obtained by removal of the acetyl group. Condensation of this acid with an aminopiperidine could be achieved by means of the mixed anhydride (prepared by reaction with ethyl chlonoformate), which affords clebopride (145). Reaction with 3-aminoquinuclidine (146) of the intermediate prepared from acid 144 with carbonyldiimidazole affords zacopride (147) [36]. 

Ethyl Benzoate.—This ester has not been found, so far, to occur naturally in essential oils. It has, however, been prepared by synthetic processes, for example, by condensing ethyl alcohol with benzoic acid by means of dry hydrochloric acid gas. Its odour is very similar to that of methyl benzoate (q.v.), but not quite so strong. It is an oil of specific gravity I OfilO, refractive index 1 5055, and boiling-point 213° at 745 mm. It is soluble in two volumes of 70 per cent, alcohol. 

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