Preparation of mono-labelled aliphatic polyacids via isoxazole derivatives

A method allowing the selective oxygen labelling of aliphatic polyacids, for example, succinic and glutaric acids, is reported. This process is based on the hydrolysis of a 3-alkyl-4-nitroisoxazol-5-yl group by Na18OH and affords the products in high yields. The same procedure was applied for the preparation of labelled aliphatic carboxylic acids.