Dehydrocyclization of 3-(hydrogermyl)propanoic acid and its derivatives

3-(Hydrogermyl)propanoic acid and N-(3-(hydrogermyl)propanoyl)-amino acids were transformed to the corresponding 5- or 8- membered germalactones under reduced pressure through intramolecular dehydrocyclization in the absence of catalyst in good yields. A series of 5- and 8- membered germalactones we re synthesized. Biological tests showed that four of these cyclic compounds possess moderate antitumor activity.