Malonic acid Homologues

Yield.—84% theoretical (95 gms.). Colourless crystals easily soluble in water, alcohol, and ether M.P. 132° loses carbon dioxide yielding acetic acid at 140°—150°. All malonic acid homologues react similarly (see Reaction XXXIII. (b)). (A., 204, 125 B 22, [2], 400.)... 

From these esters the corresponding dibasic acids can be obtained by hydrolysis, so that the homologues of malonic acid can be synthesised in this way. 

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. 

The homologues of succinic acid are analogous to those of malonic acid and are formed by the introduction of alkyl radicals into the carbon groups that are not carboxyl in character. As succinic acid contains two such carbon groups, each of which has two replaceable hydrogens, we may have the introduction of one, two, three or four alkyl radicals. Taking, as an illustration, the methyl substitution products of succinic acid we may have the following compounds ... 

Small molecules can have near-homologues for antagonists, e.g. malonic acid 9,3) antagonizes the oxidation of succinic acid 9,4) by succinic dehydrogenase (Quastel and Wooldridge, 1927). 

Aminophenyl)malonic acid ester amides (263) undergo base-catalysed cyclization to afford 1,5-benzodiazepinediones (264) and (265). By contrast, the homologue (266) gives the benzimidazole derivative (267) rather than the... 

Elimination of CO2.— Malonic acid and its homologues readily lose CO2 when heated to a temperature of about 140-160°. This reaction also takes place at a lower temperature when a solution of the dicarboxylic acid in 20 per cent H2SO4 is refluxed. The... 

Reaction XLIV. (b) Condensation of Alkyl and Aryl Halogen Compounds with the Sodio- and other Metallo-derivatives of Ethyl Aceto-acetate and its Homolognes. (A., 186, 214 201, 143 213, 143.)—Like malonic ester, acetoacetic ester contains two 1 3-carbonyl groups with a methylene group in position 2. It is only to be expected then that it yields with metallic sodium or sodium alcoholate sodio-derivatives from which mono- and di-, alkyl and aryl homologues can be obtained by treatment with a suitable halide, including halogen esters. Acetoacetic acid... 

Higher saturated ahphatic dicarboxyhc acids, such as malonic, succinic and glutaric acids and other higher homologues of oxahc acid, are found in many food raw materials and foods, but usuahy in smaher quantities. They are mainly intermediates of fatty acids biosynthesis, the citric acid cycle and other metabohc processes, but only succinic acid occurs in a somewhat larger amount in some fruits (e.g. in currants and strawberries). Ah the above mentioned dicarboxyhc acids, including oxahc, adipic, pimehc, suberic acids... 

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