Preparation of quinic acid derivatives

A process for the production of 3- and/or 4-substituted quinic acid derivatives, in which the substituent in the 3 position is different from the substituent in the 4 position and in which a derivative of a hydroxycinnamic acid, of which the hydroxyl group(s) is/are protected, is reacted with a protected derivative of quinic acid to form an ester and the protective groups are subsequently cleaved, characterized in that the quinic acid derivative used is a quinide, in that the esterification or the introduction of a protective group in the case of the 4-substituted derivatives is carried out regioselectively in the 3 position of the quinic acid skeleton at a temperature below -10.degree. C., in that the protective groups are cleavable under controlled acidity and temperature conditions and in that, when it is desired to prepare the final quinic acid, the quinide is subjected to acidic hydrolysis under controlled conditions, the controlled conditions enabling any degradation or isomerization to be avoided.