6-O-Sulfated Modification of Natural Glycoalkaloids Chaconine and Solanine1

Glycoalkaloids (GAS) have important biological and pharmaceutical activities. In order to study the relationship between the structures and the activities of carbohydrate chains, two natural glycoalkaloids, chaconine (compound 1) and solanine (compound 2), were isolated from potato stems and leaves (Solanum tuberosum L.). The selective sulfation to the 6-hydroxy groups of chaconine and solanine was carried out in a strategy by the use of protective groups. The 6-hydroxyl groups of the sugar chains in chaconine and solanine were protected with 4,4′-dimethoxytrityl (DMT) while the other hydroxyl groups were acetylated. The protective group DMT was removed by using 0. 5% TFA in dichloromethane. The free 6-hydroxyl groups were sulfated by chlorosulfonic acid pyridine to give 6-0-sulfated products. After the acetyl groups were lemoved, the final products obtained were sulfated chaeonine and sulfated solanine. 13C NMR spectra confirmed that chaconine and solanine were sulfated at 06 of the carbohydrate moiety.