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Download Nomenclature of Carboxylic Acids 1. Parent alkane + the suffix
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Gentilucci, Carboxylic acids Nomenclature of Carboxylic Acids 1. Parent alkane + the suffix -oic acid 2. Select the longest continuous carbon chain, containing the carboxylic acid. 3. Number the carbon chain, beginning at the end nearest to the carboxylic acid. 4. Number the substituents and write the name, listing substituents alphabetically. Carboxylic acid substituents attached to rings are named using the suffix -carboxylic acid. Gentilucci, Carboxylic acids Physical properties Polar compounds H-bonds pKa = 4.76 Acidity 1 Gentilucci, Carboxylic acids Synthesis of carboxylic acids Oxidation of aromatic side-chains with warm neutral permaganate Primary alcohols can be oxidized smoothly to the corresponding carboxylic acid with either CrO3/H2SO4 or sodium dichromate. Gentilucci, Carboxylic acids Acidic MnO4- will oxidize an alkene to the corresponding carboxylic acid. Terminal alkenes are converted to CO2. Acidic MnO4- will oxidize a ketone to the corresponding carboxylic acid. The reaction is slower than the oxidation of alkenes, allowing disubstituted alkene carbons to be oxidized to the ketone, without significant over-oxidation. Aldehydes are smoothly oxidized to the corresponding carboxylic acid with either CrO3/H2SO4 or sodium dichromate. Aldehydes (but not ketones) are oxidized by Ag2O in aqueous ammonia to give the carboxylic acid and metallic silver: the "silver mirror" (Tollens test). 2 Gentilucci, Carboxylic acids Nitriles can be hydrolyzed to the corresponding carboxylic acids (heat and concentrated acid). Grignard reagents react with CO2 to yield carboxylic acids. This is an important method for the preparation of carboxylic acids and yields are generally good. Gentilucci, Carboxylic acids Reduction Carboxylic acids can be reduced to primary alcohols with LiAlH4 or with BH3 followed by work-up with aqueous acid. In the reduction with LiAlH4, an intermediate aldehyde is formed, which is rapidly reduced to give the primary alcohol. Reduction by H2 / Pd and by NaBH4 are uneffective! Selective reduction of other functional groups (alkene, ketone...) in the presence of a carboxylic acid is possible. 3 Gentilucci, Carboxylic acids Acid halides Carboxylic acids can be converted into acid halides by reaction with SOCl2, phosgene, oxalyl chloride, or PBr3. Gentilucci, Carboxylic acids Esterification Carboxylic acids can be converted into esters by reaction with the corresponding alcohol in the presence of an acid catalyst (Fischer), by alkylation of the carboxylate anion with an alkyl halide in an SN2 reaction, or by reaction with diazomethane (methyl esters only). 4 Gentilucci, Carboxylic acids Fischer esterification Gentilucci, Carboxylic acids Decarboxylation of diacids, beta-keto acids, malonic acid derivatives 5
