2-Methylbutanoic acid
2-Methylbutanoic acid is a chemical compound from the group of carboxylic acids. It occurs in two enantiomeric forms, - and -2-methylbutanoic acid. -2-Methylbutanoic acid occurs naturally in cocoa beans and -2-methylbutanoic occurs in many fruits such as apples and apricots. The ethyl ester is found in pineapples and oranges.
2-Methylbutanoic acid was the product of the first enantioselective synthesis in 1905 when the German chemist W. Marckwald heated ethylmethylmalonic acid with the chiral base brucine and obtained an optically active product mixture. Both enantiomers of 2-methylbutanoic acid can be obtained by asymmetric hydrogenation of tiglic acid using a Ru-BINAP catalyst.
2-Methylbutanoic acid is a slightly volatile, colorless liquid with an unpleasant odor that is sparingly soluble in water. The smell differs significantly between the two forms. -2-Methylbutyric acid has a pleasantly sweet, fruity odor. -2-methylbutanoic acid has a pervasive, cheesy, sweaty odor.
