Ethyl benzoate, preparation reactions

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... 

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). 

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. 

Variations of the above procedures are sometimes employed. /S-Keto esters may be obtained by alcoholysis of the intermediate diacyl esters by sodium methoxide in methanol, as in the preparation of methyl /3-oxocaprylate (88%). The starting /S-keto ester can be converted to the new /S-keto ester in a single step. Thus, in the synthesis of ethyl ben- > zoylacetate (55%)> ethyl acetoacetate and ethyl benzoate are converted directly to this keto ester by distilling the lower-boiling product, ethyl acetate, thereby forcing the reaction to completion. ... 

Triphenylmethanol can also be prepared from the reaction of ethyl benzoate with phenylmagnesium bromide and by the reaction of diethylcarbonate... 

Roberts and Whiting developed a method for effecting the anhydrous hydrolysis of esters and nitriles in DMSO. A solution of sodium methylsulfinylmethide is prepared from sodium hydride and DMSO and titrated with a solution of an appropriate amount of water in DMSO, using triphenylmethane as indicator. This produces a fine suspension of sodium hydroxide which hydrolyzes ethyl benzoate very rapidly at room temperature. As compared with reactions in hydroxylic solvents, rates are enhanced by a factor of 10 -10 . Benzonitrile is hydrolyzed to benzamide. Methyl and ethyl mesitoates are hydrolyzed readily at 25°. 

The most important species in the mechanism for ester hydrolysis is the tetrahedral intermediate. Evidence in support of the existence of the tetrahedral intermediate was developed by Professor Myron Bender on the basis of isotopic labeling experiments he carried out at the University of Chicago. Bender prepared ethyl benzoate, labeled with the mass-18 isotope of oxygen at the carbonyl oxygen, then subjected it to acid-catalyzed hydrolysis in ordinary (unlabeled) water. He found that ethyl benzoate, recovered from the reaction before hydrolysis was complete, had lost a portion of its isotopic label. This observation is consistent only with the reversible formation of a tetrahedral intermediate under the reaction conditions ... 

The hydantoin 34 on treatment with ethyl formate in the presence of sodium gave the tricyclic compound 35, which could be methylated with diazomethane to the 2-methyl derivative 37a. This compound could also be obtained from the hydantoin 36 using ethyl formate. Ethyl acetate gave the corresponding 4-methyl derivative 37b. No reaction occurred during attempts to prepare 37 (R = Ph) using ethyl benzoate. ... 

Scheibler733 has described a laboratory method of preparing acetoacetic ester that is convenient and gives very good yields. In industry it is obtained by use of sodium dust in autoclaves, quantitative yields being claimed734 for this process. Occasionally acetoacetic ester is prepared by condensation of ethyl acetate and used, without isolation, for further reactions, whereby excellent yields of the final products are obtained.735 Ethyl benzoate and acetophenone give dibenzoylmethane in about 70% yield.736 0-Hydroxy-acetophenone, condensed with ethyl propionate and sodium in ether, afford l-(0-hydroxyphenyl)-l,3-pentanedione which is cyclized to 2-ethylchromone in 70-75% yield by hydrochloric and acetic acid.737... 

Benzoyl chloride is a liquid of disagreeable odor, which is insoluble in water, and boils at 194°. It resembles acetyl chloride in its behavior, but does not enter into reaction so readily. It is decomposed but slowly by cold water or alcohol. The reaction between benzoyl chloride and alcohols is much facilitated by the presence of an alkali. Ethyl benzoate may be prepared by shaking an aqueous solution of alcohol and sodium hydroxide with benzoyl chloride (Baumann and Schotten reaction) —... 

R = Ph) " have been prepared by reaction of blue ruthenium(III) chloride with the corresponding diketone under basic conditions or by ligand exchange with [Ru(acac)3]. The tris chelate complexes of (-t-)-3-acetylcamphor and (-i-)-3-trifluoroacetylcamphor [RUL3], for example, have been prepared by ligand exchange reaction with [Ru(acac)3] in ethyl benzoate at 160°C the diastereomers have been separated by tic on silica and assigned by H NMR studies. For tris complexes of... 

For example, the reaction of ethyl benzoate with 1.3 equiv of /-Bu2AlTeBu, prepared in situ by Ogura s method from BuTeTeBu and 2 mol equiv of DIBALH at 25 °C in toluene in the presence of a catalytic amount of PPh3 for 20 h [121], affords the tellurol ester in 82% yield. This transesterification proceeds smoothly in nonpolar solvents such as toluene and n-hexane. Aryl esters react efficiently in comparison with alkyl esters. Addition of a catalytic amount of PPh3 or ZnCl2 accelerates the reaction and improves the yields. Substituents on the oxygens of the esters exert significant steric effects on this reaction, but the reaction is insensitive to the steric bulkiness of substituents on the carbonyl carbon. 

Acyloin condensation. The usual preparation of acyloins from aliphatic esters is not applicable to aromatic esters. In this case the reaction with sodium results in formation of the sodium carboxylate and a radical from the R group which undergoes further reactions. However, benzoin can be prepared in moderate yield by treatment of the trimethylsilyl ester of benzoic acid with sodium or by treatment of ethyl benzoate with sodium naphthalenide in THF at room temperature (397 yield). ... 

A student prepares ethyl benzoate by the reaction of benzoic acid with ethanol using a sulfuric acid catalyst. The following compounds are found in the crude reaction mixture ethyl benzoate (major component), benzoic acid, ethanol, and sulfuric acid. Using a handbook, obtain the solubility properties in water for each of these compounds (see Technique 4). Indicate how you would remove benzoic acid, ethanol, and sulfuric acid from ethyl benzoate. At some point in the purification, you should also use an aqueous sodium bicarbonate solution. Outline your procedure using a flowchart (see Section 12.12). 

When used in THF at room temperature, the base prepared from LiTMP and CoBr in a 3 1 ratio proves capable of deprotometalating different methoxybenzenes. The generated aryhnetal species can be trapped by different electrophiles iodine, anisaldehyde, and chlorodiphenylphosphine to respectively generate the corresponding iodide, alcohol, and phosphine in high yields and benzo-phenone, benzoyl chloride, and allyl bromide to afford the expected alcohol, ketone, and allylated compound in moderate yields (Table 27.10). The side formation of symmetrical dimers was observed in the course of these reactions, in particular using aUyl bromide such a side reaction (reduced by using the base in excess) could be initiated by one-electron transfer from a cobaltate species to the electrophile. This lithium-cobalt base is not suitable for the functionalization of sensitive substrates such as ethyl benzoate [109,110]. 

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