Carboxylic acid

About: Carboxylic acid is a research topic. Over the lifetime, 48544 publications have been published within this topic receiving 605696 citations.

Mechanism of Polyphosphoric Acid and Phosphorus Pentoxide−Methanesulfonic Acid as Synthetic Reagents for Benzoxazole Formation

Abstract: The mechanism of 2-phenylbenzoxazole formation from benzoic acid and o-aminophenol in polyphosphoric acid (PPA) is studied by NMR spectroscopy and chemical analysis. Benzoic acid reacts with PPA to form benzoic−phosphoric anhydride and benzoic−polyphosphoric anhydride. The ratio of mixed anhydride to free carboxylic acid increases dramatically as the P2O5 content of PPA increases, but this ratio is independent of reaction temperature and time. When o-aminophenol dissolves in PPA, part of the hydroxyl group is converted to phosphate ester, and only protonated amine is detected. Benzoic acid, mixed anhydride, and PPA are in dynamic equilibrium, and so are PPA, o-aminophenol, and its phosphate ester. The mixed anhydride and o-aminophenol react to form 2-aminophenyl benzoate as the first reaction intermediate which undergoes rapid acyl migration to generate 2-hydroxybenzanilide. Ring closure of 2-hydroxybenzanilide to form 2-phenylbenzoxazole is acid catalyzed. The reactive components in phosphorus pentoxide−...

Microwave-assisted Cu-catalyzed protodecarboxylation of aromatic carboxylic acids.

Abstract: An effective protocol has been developed that allows the smooth protodecarboxylation of diversely functionalized aromatic carboxylic acids within 5−15 min. In the presence of at most 5 mol % of an inexpensive catalyst generated in situ from copper(I) oxide and 1,10-phenanthroline, even nonactivated benzoates were converted in high yields and with great preparative ease.

Total synthesis of (±)-forskolin

Abstract: Preparation a partir d'un trimethyl-2,4,4 vinyl-3 cyclohexene-2ol (issu de l'α-ionene) et de l'acide tosyl-3 propiolique