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Malonic acid reacts as a typical carboxylic acid forming amide, ester, and chloride derivatives. [13] Malonic anhydride can be used as an intermediate to mono-ester or amide derivatives, while malonyl chloride is most useful to obtain diesters or diamides. In a well-known reaction, malonic acid condenses with urea to form barbituric acid.
In this reaction the carbonyl group is an aldehyde or a ketone. The catalyst is usually a weakly basic amine. The active hydrogen component has the forms: [3] Z−CH 2 −Z or Z−CHR−Z for instance diethyl malonate, Meldrum's acid, ethyl acetoacetate or malonic acid, or cyanoacetic acid. [1] Z−CHRR', for instance nitromethane.
In forming diethyl malonate from malonic acid, the hydroxyl group (−OH) on both of the carboxyl groups is replaced by an ethoxy group (−OEt; −OCH 2 CH 3). The methylene group (−CH 2 −) in the middle of the malonic part of the diethyl malonate molecule is neighboured by two carbonyl groups (−C(=O)−). [4]
Disodium malonate is a sodium salt of malonic acid with the chemical formula CH 2 (COONa) 2. It is a white crystal soluble in water but not in alcohols, esters or benzene. It can be prepared from the reaction of sodium hydroxide and malonic acid: CH 2 (COOH) 2 + 2 NaOH → CH 2 (COONa) 2 + 2 H 2 O
Dimethyl malonate is a diester derivative of malonic acid. It is a common reagent for organic synthesis used, for example, as a precursor for barbituric acid. It is also used in the malonic ester synthesis. It can be synthesized from dimethoxymethane and carbon monoxide. [2]
A notable method for synthesizing acetamidomalon ester is described in a 1950 patent, [1] which cites a procedure previously featured in Organic Syntheses. [2] The synthesis procedure involves the preparation of malonic acid diethyl ester in acetic acid combined with sodium nitrite (NaNO 2), resulting in diethyl isonitrosomalonate (also known as α-oximinomalonic acid diethyl ester).
Malonyl chloride can be synthesized from malonic acid in thionyl chloride. [3] As a bifunctional compound , it is used in the preparation of a number of cyclic compounds by di acylation . Heating in the presence of non-nucleophilic base gives the ketene derivative O=C=C(H)COCl.
Diethyl oxomalonate is the diethyl ester of mesoxalic acid (ketomalonic acid), the simplest oxodicarboxylic acid and thus the first member (n = 0) of a homologous series HOOC–CO–(CH 2) n –COOH with the higher homologues oxalacetic acid (n = 1), α-ketoglutaric acid (n = 2) and α-ketoadipic acid (n = 3) (the latter a metabolite of the amino acid lysine).