Benzoylation of acetoacetic ester

Benzotriazole, 20,16 Benzoylacetic ester, 23, 35 Benzoylation of acetoacetic ester by ethyl benzoate, 23, 35 Benzoyl chloride, 24, 14 purification of, 24, 15 Benzoyl Cyanide, 24,14, 16 Benzoyleormic acid, 24,16 Benzoyl-o-toluidines, conversion to indoles, 22, 95... 

Bernhard, A. Benzoylation of acetoacetic esters. Liebigs Ann. Chem. 1894, 282,153-191. 

Benzotriazole, 20, 16 Benzoylacetanilide, 25, 7 Benzoylacetic ester, 23, 35 Benzoylation of acetoacetic ester by... 

To 600 c.cs. of absolute alcohol in a flask attached to a reflux are gradually added 35 gms. (2 atoms) of sodium cut in small pieces. When all the sodium has dissolved, the solution is cooled. To 300 c.cs. of this solution are added 100 gms. (1 mol.) of acetoacetic ester, and, with continual stirring, 45 c.cs. of benzoyl chloride are dropped in from a burette during 15 minutes, the temperature being kept below 10°. After 30 minutes, 150 c.cs. of the original solution and 22 c.cs. benzoyl chloride are added as before. This process is repeated until all the original solution is used up, and 90 c.cs. benzoyl chloride in all. After 12 hours, the sodium salt is filtered off and washed with ether. By acidifying with dilute acetic... 

Similarly, the a-methylene group of acetoacetic ester is oximinated by the action of sodium nitrite in glacial acetic acid (63%). Nitrosation of alkylated malonic, acetoacetic, and benzoyl acetic esters with subsequent cleavage affords an excellent synthesis for a-oximino esters, RC(=-NOH)COjC2Hj. A survey of several possible procedures for this conversion has been made." If a /3-keto acid is nitrosated, then the Carboxyl group is lost and an a-oximino ketone is formed, viz.,... 

Esters of pyridazinyl-3-acetic acid 60 can be prepared when, for example, 3-methoxypyridazine I-oxide reacts with methyl )3-aminocrotonate in the presence of benzoyl chloride to give 59. Since )8-aminocrotonic esters are tautomeric with the imines of acetoacetic esters, mild acid hydrolysis converts them into the corresponding acetoacetic ester and then to ester 60 (78JHCI425). 

Benzoylacetone can also be benzoylated by the method just detailed but the product, acetyldibenzoylmethane, is more conveniently obtained by another method due to Claisen 426 this second method can also be used for benzoylation of acetoacetic and malonic esters though the yields are there not as good the procedure is to treat a mixture of benzoyl chloride and benzoylacetone in boiling ether with anhydrous sodium carbonate, as follows ... 

The ester so obtained,uniijce most acetoacetic ester derlvatires,may be hydrolyzed to the free acid without decomposition. Their general behavior is like that of the 1,1 diacid,the same reactivity of the ring being characteristic of both the benzoyl and acetyl compounds. The ester when treated with cold hydro-bromic acid gives y-bromethylacetacetic esterif the acid is used,carbon dioxide is evolved andy -brom-propyl jcetone results ... 

Benzoylhydrazine reacts with ethyl acetoacetate at 130 °C in the absence of solvent to give first the pyrazolone (295 R = PhCO). Water from the reaction hydrolyzes the benzoyl group and a second molecule of the ester reacts to give the pyranopyrazolone (296) (63BSF2742). The aminopyrazolones (297) and carbon disulfide give the zwitterionic pyrazolothiazines (298) which S,5-dialkylate with diazomethane or alkyl iodides (78FES799). 

Problem 26.7 (a) Predict the product of the acetoacetic ester synthesis in which ethyl bromoacetate (why not bromoacetic acUH) is used as the halide. To what general class of compounds does this product belong (b) Predict the product of the acelo-acelic ester synthesis in which benzoyl chloride is used as the halide in which chloro-acetone is used as the halide. To what general classes of compounds do these products belong ... 

Acetophenone possesses the properties characteristic of aromatic compounds. When heated with dilute nitric acid it is oxidized to benzoic acid with concentrated nitric acid nitro derivatives are formed. The chief product of nitration is m-nitro-acetophenone a small proportion of the ortho compound is also formed. p-Nitroacetophenone can be prepared from p-nitro-benzoyl chloride and acetoacetic ester. 

Acyloin synthesis. In a novel synthesis by Lawesson and Gronwall t-butyl acetoacetate is prepared from diketene and t-butanol and alkylated, and the benzoyl oxy group is introduced in the a-position by reaction of the sodio derivative with dibenzoyl peroxide. Elimination of the /-butyl group and decarboxylation is accomplished by heating the ester at 160° with a catalytic amount of p-toluenesulfonic... 

Sodium (35.4 g) is dissolved in ethanol and the solution is made up to a known volume (600 ml). Half of this sodium ethoxide solution is mixed in the cold with ethyl acetoacetate (100 g) this mixture is cooled to 5° and stirred while benzoyl chloride (45 ml) is then added during about 15 min and the temperature is not allowed to exceed 10°. The solution is next set aside for 30 min, after which half of the residual sodium ethoxide solution (i.e., 150 ml) is added in one portion, followed, gradually this time, by benzoyl chloride (22.5 ml), and again the mixture is set aside for a short time. This procedure is repeated, each time with half the previous amounts of ethoxide and benzoyl chloride, until all the material has been added. Meanwhile a mixture of sodium chloride and ethyl sodiobenzoylacetoacetate has separated from the alcoholic solution. The final mixture is set aside for a further ca. 12 h in the cold, then the solids are filtered off and washed with ether. The wash-ether precipitates a further amount of sodium enolate from the filtrate and this is added to the main fraction of solids. The crude sodium enolate is briefly dried, then dissolved in a three-fold amount of water and treated, with ice-cooling, with acetic acid until no more oil is precipitated. This oily product is taken up in ether, dried over calcium chloride, and fractionated the desired ester has b.p. 175-176°/12 mm. 

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