By the malonic ester synthesis

By the malonic ester synthesis (compare Section 111,165), for example ... 

Monoalkylated and dialkylated acetic acids can be prepared by the malonic ester synthesis, but trialkylated acetic acids (R3CCO2H) can t be prepared. Explain. 

Among the ether acids prepared by the malonic ester synthesis are 6-phenoxycaproii. acid (65% over-all) from S-phenoxybutyl bromide ana y-(o-anisyl)-butyric acid (80%) from /3-(o-anisyl)-ethyl bromide/ ... 

Few acids have been prepared by this method. It is important in the preparation of diisopropylacetic acid, which is made with difficulty by the malonic ester synthesis. Ethyl cyanoacetate is readily alkylated ... 

Several of the homologues of malonic acid are known and they may all be prepared by the malonic ester synthesis as described above. A few of these will be mentioned simply by giving their formulas. 

From Aceto-acetic Ester.—Glutaric acid may also be made by either the aceto-acetic ester synthesis or by the malonic ester synthesis as follows,... 

From Malonic Ester.—By the malonic ester synthesis it results from the condensation of two molecules of the malonic ester with di-iodo methane, methylene iodide, or with form-aldehyde, and the subsequent loss of carbon di-oxide from the condensation product, as follows ... 

In planning a malonic ester synthesis, our problem is to select the proper alkyl halide or halides to do this, we have only to look at the structure of the acid we want. Isocaproic acid, for example, (CH3)2CHCH2CH2COOH, can be considered as acetic acid in which one hydrogen has been replaced by an isobutyl group. To prepare this acid by the malonic ester synthesis, we would have to use isobutyl bromide as the alkylating agent ... 

In place of simple alkyl halides, certain other halogen-containing compounds may be used, in particular the readily available a-bromo esters (why can a-bromo-acids not be used ), which yield substituted succinic acids by the malonic ester synthesis. For example ... 

Tridecylic acid has been prepared by the malonic ester synthesis from undecyl iodide,1 by the oxidation of a-hydroxymyristic acid in acetone with potassium permanganate,2 by the action of dodecyl bromide on potassium cyanide and subsequent hydrolysis,3 and from undecyl iodide and ethyl cyanoacetate.4 The present method is an adaptation of that of Ruzicka, Stoll, and Schinz.3... 

The first reaction shown in the passage described the synthesis of a carboxylic acid (2,2-dimethyl-4-phenylbutanoic acid) in which the a carbon is quaternary. What is the maximum degree of substitution at the a carbon of a carboxylic acid prepared by the malonic ester synthesis ... 

More complicated structures can be prepared by the malonate ester synthesis. It is possible to introduce a second alkyl group by repeating the steps outhned above using either the same alkyl group or a different one. 

What reactants are required to prepare 3-ethylpentanoic acid by the malonate ester synthesis ... 

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