Ethyl benzoate preparation

Uses of hydrogen chloride—Hydrogen chloride is sometimes used in the preparation of an ester, for example ethyl benzoate, where it acts as both an acid catalyst and a dehydrating agent. Hydrochloric acid is used primarily to produce chlorides, for example ammonium chloride. It is extensively used in the manufacture of anilme dyes, and for cleaning iron before galvanising and tin-plating. 

As a general rule esterification by the Fischer-Speier method should be carried out using absolute cthanob in the following preparation of ethyl benzoate, however, the yield is not sensibly affected by the use of the cheaper rectified spirit. 

Cinnamic acid can be readily esterified by the Fischer-Speier method without any risk of the addition of hydrogen chloride at the double bond. Proceed precisely as for the preparation of ethyl benzoate (p. 104), using 20 g. of cinnamic acid and 20 ml. of rectified spirit. When the crude product is poured into water, a sharp separation of the ester is not readily obtained, and hence the addition of about 10 ml. of carbon tetrachloride is particularly desirable. Finally distil off the carbon... 

Quantitative Hydrolysis of Ethyl Benzoate -The quantitative estimation of an ester Ijy hycliolysis is conducted as follows a standaid half-normal solution of alcoholic potash is prepared by dissolving 7 grams of caustic potash m about an equal weight of water and diluting to 250 c.c. with absolute alcohol. The liquid is alloived to stand ovei night in a stoppered... 

Ethyl Benzoate.—The method of Fischer and Speler foi the preparation of esters, by boiling together the acid with the alcohol containing about 3 per cent, of either hydroclaloric acid... 

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. 

Dibenzoylmcthane has been prepared by the hydrolysis of dibenzoyl acetic acid 1 by the slow spontaneous decomposition of acetyl dibenzoyl methane 2 by the action of metallic sodium,3 sodium ethylate,3 sodium methylate,4 alchoholic potash,4 or sodamide 5 on mixtures of acetophenone and ethyl benzoate and by the action of alcoholic potash,6 sodium methylate,7 or sodium ethylate 8 on benzalacetophenone dibromide. 

Ethyl benzoylacetate has been prepared by the condensation (by means of sodium ethylate) of ethyl acetate with ethyl benzoate,1 acetophenone with ethyl carbonate,2 and acetophenone with ethyl oxalate, with subsequent heating 3 by treatment of ethyl phenylpropiolate4 or a-bromocinnamic acid 5 with concentrated sulfuric acid, and of ethyl diazoacetate with benzalde-hyde 6 by the condensation of benzene with the monoethyl ester of malonyl monoacid chloride and aluminum chloride,7 of benzoyl chloride with the product of the reaction of magnesium and ethyl chloroacetate in ether,8 of alcohol on benzoylacetimino ethyl... 

Following are the percentage yields obtained in the preparation of other esters ethyl maleate, 73 ethyl salicylate, 70 ethyl oxalate, 80 ethyl benzoate, 92 methyl benzoate, 87. In the preparation of ethyl maleate troublesome emulsions were encountered in working up the product. Occasionally this hap-... 

B. Phenylglyoxal. The phenylglyoxal hemimercaptal prepared as described in procedure A (69-74 g.) is dissolved in 400 ml. of warm chloroform, and 60 g. (0.30 mole) of powdered cupric acetate monohydrate is added in one portion to the well-stirred solution. The mixture is stirred at room temperature for 1 hour the solids are removed by suction filtration and washed with two 75-ml. portions of chloroform. The combined chloroform filtrate and washings are shaken in a separatory funnel with 75 ml. of water 20 g. of powdered sodium carbonate is added in small portions to the funnel, and the chloroform solution is shaken with the neutralized aqueous solution. (Cautionl Carbon dioxide is evolved.) The aqueous layer is separated and extracted with four 30-ml. portions of chloroform. The chloroform solutions are combined and dried with anhydrous magnesium sulfate, and the chloroform is removed under reduced pressure. The residue is fractionally distilled under reduced pressure to yield 43-49 g. (64-73%, based on ethyl benzoate) of anhydrous phenylglyoxal as a yellow liquid, b.p. 63-65° (0.5 mm.). 

The simplest method for preparing alkylene oxides involves the use of benzoyl peroxide (Prileschaiev). In absolute ether or, still better, in benzene solution, it is broken by sodium ethoxide into the sodium salt of perbenzoic acid and ethyl benzoate.1... 

Ethyl benzoate is prepared in a similar way, by boiling benzoic acid (30 g.) in 100 c.c. of absolute alcohol for four hours under reflux condenser with 3 c.c. of concentrated sulphuric acid. Most of the alcohol is then removed by distillation, 300 c.c. of water are added,... 

Benzoylacetone. — C6H5.CO.CH2.CO.CH3 is prepared in an analogous way from acetophenone and ethyl acetate according to the procedure of Claisen, Ber., 1905, 38, 695. The yield may be as much as 75 per cent of the theoretical. The cheaper converse method—action of sodamide on ethyl benzoate and acetone—also succeeds in this case, although it fails when sodium or sodium ethoxide is used as condensing agent. In general the use of sodamide is to be preferred in the synthesis of 1 3-diketones. 

Ethyl benzoate (15 g.) mixed with 15 c.c. of absolute ether is dropped into a Grignard solution prepared as just described from 6-4 g. of magnesium and 40 g. of bromobenzene. The conditions are the same as those observed in the preceding preparation at the end the solution is boiled for half an hour and worked up as before. Colourless prisms of triphenylcarbinol, melting point 162°, are obtained by recrystallising the solid residue from hot alcohol. Yield over 20 g. For further information about this important alcohol see p. 355. 

Other hydrides used for the conversion of esters to alcohols are magnesium aluminum hydride in tetrahydrofuran [89, 577] and magnesium bromohydride prepared by decomposition of ethylmagnesium bromide at 235° for 2.5 hours at 0.5mm [7055]. They do not offer special advantages (the latter giving only 35% yield of benzyl alcohols from ethyl benzoate). 

Methyl />-acetylbenzoate has been prepared by the esterification of -acetylbenzoic acid with methanol in the presence of hydrogen chloride,6 by the hydrogenation of methyl -trichloro-acetylbenzoate in the presence of a palladium on calcium carbonate catalyst,6 and by the air oxidation of methyl / -ethyl-benzoate.4... 

Benzoxathiolium salts have proven to be effective masked acylating agents (79S223). 2-Substituted 1,3-benzoxathiolium tetrafluoroborates have now been utilized in the preparation of esters. Reaction of the salt (334) with two equivalents of an alcohol gave the 2-alkoxy-2-alkyl-benzoxathiole (335). Hydrolysis of (335) with red mercury(II) oxide and boron trifluoride etherate in aqueous THF delivered ethyl benzoate in excellent yield (Scheme 72). 

Cyclization of 2-[(3-acetamido-2-pyridyl)amino]benzoic acid (202) in 0.5 N sulfuric acid gave 6-amino-ll//-pyrido[2,l-h]quinazolin-ll-one (203) (84MI3). 2-[(6-Methyl-, 5-nitro-, and 3-nitro-2-pyridyl)amino]benzoic acids were cyclized into 9-methyl, 8-nitro, and 6-nitro-l 1 //-pyrido[2,l -ujquina-zolin-ll-ones, respectively, by the action of 80% sulfuric acid. Ethyl 2-(2-pyridylamino)benzoate, prepared in the reaction of 2-chloropyridine and ethyl anthranilate in boiling toluene for 10 h, afforded ll//-pyrido[2,l-b]-quinazolin-ll-one (27) on heating at 200-210°C for 0.5 h (92MI2). 

Preparation 201.—Ethyl Benzoate (Ethyl ester of benzoic acid). 

Ethyl benzoate, glyceryl tri-benzoate, etc., are prepared in an exactly similar manner. The reaction can also be applied to phenols and naphthols. 

Aryl iodides. Aryl iodides can be prepared by reaction of arenes with I2 and a mixture of A1C13 and CuCI 2. Yields are moderate to good, but the reaction fails with ethyl benzoate, acetophenone, and o-nitroanisole. The reagents are used in the ratio I2 A1C13 CuCl2 = 0.5 1 1. 

The mono-strapped complex 98, which is prepared by the ethyl benzoate displacement method (Section II. C), has planar chirality owing to the presence of different 1,3-substituents on the r 6-arene and can be separated into its enantiomers by chiral HPLC. Each enantiomer reacts with AgOTf/H20 to give the corresponding di-strapped aqua cation in which a second chiral centre is present because there are now three different groups in the tripodal set. However, each... 

Gomberg and Pemert4 recommended the use of the sodium diazotates for the preparation of biaryls from aniline and from p-toluidine and the normal diazo method for negatively substituted amines such as the bromo- and nitro-anilines. Grieve and Hey 7 found little difference in the yields of biaryls obtained by the two procedures when they coupled diazotized aniline with six different components benzene, toluene, m-xylene, chlorobenzene, nitrobenzene, and ethyl benzoate. Where it is applicable, this modification offers the advantage that the dropwise addition of alkali is eliminated. 

Dimethyl-188 and 2,6-dimethylpyrazine react very similarly to methylpyrazine. Thus, 2,6-dimethylpyrazine can be converted into a monoanion with sodamide in liquid ammonia which can be condensed with aldehydes and ketones,179 acylated with esters,181 and alkylated with alkyl halides181 to give the corresponding 2-methyl-6-substituted pyrazines. Acylation under suitable conditions also yields diacylated derivatives. Thus, when 2,6-dimethylpyrazine, sodamide, and ethyl benzoate are reacted in 1 3 2 molecular proportion, 38% 2,6-diphen-acylpyrazine (35) and 25% 2-methyl-6-phenacylpyrazine (36) is obtained. From the preparative point of view it is better to form the diacyl derivative by the further acylation of the monoacyl derivative rather than by direct diacylation.187... 

Preparation of 1,1-enediamines having a benzimidazoline ring has been reported recently by the acylation of 1,2-dimethylbenzimidazole (88) with ethyl benzoates in the presence of excess sodium hydride. Both enediamine 13 and amidine 13 isomers were obtained (equation 30)33. 

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