Ethyl malonic acid

Properties.—Colourless liquid with an agreeable fruity smell b. p. 207 sp. gr. I 008 at 

Properties.—Rhombic prisms m. p. iii 5°) easily soluble in water, alcohol, and ether. 

Reaction.— i. Heat a gram or two of the acid in a test-tube over a small flame and have at hand a second test-tuloe one-third full of lime water. The acid decomposes at i So  

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These compounds yield, on hydrolysis, the free acids, which, like all acids containing two carbo.xyl groups attached to the same carbon atom, lose COj on heating. Thus, ethyl malonic acid yields butyric acid. In this way the synthesis of monobasic acids may be readily effected. Malonic ester, moreover, may be used in the preparation of cyclic compounds as well as of tetrabasic and also dibasic acids of the malonic acid series ( Perkin). To give one illustration malonic ester, and ethylene bromide in presence of sodium alcoholate, yield triniethyleiic dicarbo.xylic ester and tetramethylene tetracarbo.xylic ester. The first reaction takes place in two steps,... 

Ethyl alcohol, 49 Ethyl benzene, 141 Ethyl benzoate, 209 Ethyl bromide, 54 Ethylene bromide, 62 Ethyl ether, 59 Ethyl malonate, 96 Ethyl malonic acid, 97 Ethyl potassium sulphate, 50 Ethyl tartrate, 115 rotation of, 120 Lykman depressimeter, 37... 

The ethyl malonic ester (10 gms.) is hydrolysed by boiling for an hour on the water-bath with strong aqueous potash containing 15 gms. of potash. The product is treated with moderately strong hydrochloric acid till neutral, and the acid is then precipitated as the calcium salt by adding a concentrated solution of calcium chloride. The salt is filtered and decomposed by strong hydrochloric acid and the free ethyl malonic acid extracted with ether. The ether extract deposits crystals on evaporation, and these may be recrystallised from a small quantity of boiling water. Colourless prisms, m.p, 111 5°, Yield, about 5 gms. 

Phenyl ethyl malonic acid diethyl ester Methylurea... 

Ethyl malonic acid, HOOC. CH(C2H6). COOH, was not adsorbed on either centre. 

Methyl ethyl acetic acid may be prepared from methyl ethyl malonic ester by hydrolysis and subsequent heating of the methyl ethyl malonic acid.1 The yield by this method, in the preparation of large quantities, is about 61 per cent of the theoretical amount based on the malonic ester used. The acid was first prepared by Saur2 from methyl ethyl acetoacetic ester. It has also been made by oxidation of the corresponding aldehyde with chromic acid.3... 

CH CHs) = (C00H)2 Methylmalonic acid. Iso-succinic acid. CH(C2H5) = (C00H)2 Ethyl malonic acid. 

H3C—C(C2H5) = (C00H)2 Methyl-ethyl malonic acid. 

The free ethyl malonic acid maybe obtained by following either of the methods given below. -... 

The solution is diluted with the same volume of water previously used to dissolve the caustic potash. To this is added carefully and with cooling concentrated hydrochloric acid, until an acid reaction may just be detected. The ethyl malonic acid is precipitated out in the form of its difficultly soluble calcium salt, by the addition of a cold solution of calcium chloride, as concentrated as possible. This is filtered off, well pressed on a porous plate, and the ethyl malonic acid liberated by treating carefully with concentrated hydrochloric acid is obtained pure as in (1). 

The ethyl malonic acid is placed in a small fractionating flask provided with a long condensing tube supported in an oil-bath at an oblique angle, so that its outlet tube is inclined upward. The mouth is closed by a cork bearing a thermometer. The acid is heated at 180°, until carbon dioxide is no longer evolved, which will require about a half-hour. The residue is distilled from the same flask in the usual way the butyric acid passes over between 162-163°. Yield, about 80-90% of the theory. 

Ethyl malonic acid, 162. Ethy malonic ester, 161. 

Similarly, the [M — CH3] + ions generated from the molecular ion of silylated ethyl-malonic acid 146 are believed89 to have the cyclic structure 147 from the latter the loss of C02 may proceed via a cycloreversion (147 148) (reaction 61). 

It is prepared by the interaction of diethyl ester of ethyl malonic acid and iso-pentyl chloride in the presence of sodium metal, when ethyl is isopentyl ester of diethyl malonic acid is obtained as an intermediate compound. This on condensation with urea in the presence of sodium ethoxide results into the formation of amobarbital. 

In the first step the diethyl ester of malonic acid is treated with ethyl bromide in the presence of sodium ethoxide when one of the active hydrogen atoms in the former gets eliminated with bromine atom in the later as a molecule of hydrobromic acid resulting into the formation of the corresponding diethyl ester of ethyl malonic acid. This on subsequent addition of 2-monobromopentane and in the presence of sodium ethoxide gives rise to diethyl ether of ethyl-(l-methyl butyl) malonate with the elimination of one molecule of hydrobromic acid. Urea is made to condense with the product obtained from the previous step when pentobarbital is formed with the elimination of two moles of ethanol. Finally, the pentobarbital is treated with a calculated amoimt of sodium hydroxide when the required official compoimd is formed. 

Diethyl malonate on reaction with sodium metal gives rise to sodium malonic ester which on treatment with ethyl bromide results into the formation of diethyl ester of ethyl malonic acid with the elimination of hydrobromic acid. The resulting ester on further reaction with 2-bromopentane gives the desired eompound, i.e., diethyl ester of ethyl (1-methyl butyl) malonic acid which on subsequent treatment with thiourea forms thiopental with the elimination of two moles of ethanol. Ultimately, the enol-iorm of thiopental when reaeted with a ealeulated amoimt of sodium hydroxide, it gives thiopental sodium. 

It may be prepared by the condensation of [2-(phenylsulfinyl) ethyl]- malonic acid diethyl ester with hydrazobenzene in the presence of sodium ethoxide in absolute ethanol. Completion of reaction is achieved by the addition of xylene and subsequent heating at about 130°C whereby the ethanol liberated as a produet of eondensation is removed eompletely. The crude product is extracted with a suitable solvent and finally recrystallized from ethanol. 

C]phenyl ethyl malonic acid diethyl ester and, finally, the condensation of this ester with urea. 

In order to gain better insight into this phenomenon, several X-ray analyses of 0-cyd clathrates have been undertaken. The first results of the crystal structure determination of the 3-cyd benzil complex were previously reported (1). Since then, this structure has been refined and those of benzophenone, biphenyl and phenyl-ethyl malonic acid complexes have been solved. We report herein the main features of these crystallographic studies. 

Substituted glutaric acids [29] were obtained from the ethyl malonic acid ester of the Baylis-Hillman product 14. The enolate of this ester, generated with LDA at -78 °C rearranged to give the substituted glutaric acids in good yield (Scheme 5.1.18). 

C21H40O4 2-ethyl-malonic acid dioctyl ester 1113-95-7... 

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