Decarboxylation Of Salts Research Articles

Influence of crown ethers on thermal decarboxylation of salts of perfluorocarboxylic acids

Thermal decarboxylation of potassium salts of perfluorocarboxylic acids in the presence of 20 mole % of crown ethers takes place in 1 h at 180°C and gives internal perfluoroolefins in yields of up to 95%. The predominance in product mixtures of isomers whose double bond is adjacent to the trifluoromethyl group is associated with kinetic control of the reaction. The kinetic parameters of the process have been found and the relative activities of a series of crown ethers have been established. A scheme is advanced to show their influence on the reaction studied.

Decarboxylation of salts of perfluoro-?,?-unsaturated acids

A series of poly- and perfluorinated olefins and acetylenes have been prepared from sodium and mercury salts of α,β-unsaturated perfluorinated acids by reactions which are accompanied by decarboxylation.

The Chemistry of Phthalide-3-carboxylic Acid. II. Decarboxylation of Salts in the Presence of Aldehydes

Salts of phthalide-3-carboxylic acid decarboxylate in the presence of aromatic aldehydes to give mixtures of the 3-( arylhydroxymethyl ) phthalide (2) and the 2-aryl-3-hydroxyindenone (3). The former may be obtained exclusively in the presence of the weak proton donor, triethyl (2-phenylethyl)ammonium chloride, and the latter in the presence of crown ethers or after longer reaction times. A study of the effect of different cations allows a mechanism to be deduced.

The Chemistry of Phthalide-3-carboxylic Acid. III. Decarboxylation of Salts in the Presence of α,Β-Unsaturated Ketones

Potassium phthalide-3-carboxylate (3-oxo-1,3-dihydroisobenzofuran-1- carboxylate ) decarboxylates readily in dimethyl sulfoxide at 145°, and the intermediate phthalidyl anion is efficiently trapped by α,β - unsaturated ketones. The major 1,4-addition product is accompanied by smaller amounts of an isomeric product formed by subsequent cyclization and rearrangement, and sometimes traces of a 1 : 2 1,4-addition product. The caesium salt gives slightly more cyclized product, and the lithium salt undergoes very slow decarboxylation. The synthetic usefulness of the salt decarboxylation is compared with that of the free acid.

Decarboxylation of salts of?-acetoxymercurihexafluoroisobutyric acid

1. The hydrogen atom in salts ofα-hydroperfluoroisobutyric acid is replaced when reaction is with mercuric acetate. 2. Replacing theα-hydrogen by mercury facilitates the decarboxylation of salts of hexafluoroiso-butyric acid in polar solvents.