‘Upenamide:  An Unprecedented Macrocyclic Alkaloid from the Indonesian Sponge Echinochalina sp.

‘Upenamide (1) represents a new class of macrocyclic marine alkaloid possessing both spirooxaquinolizidinone and hemiaminal ring systems. It was isolated from the Indonesian sponge Echinochalina sp. The gross structure of 1 was elucidated by spectroscopic methods and accurate mass measurements. A suggestion is made as to its biogenetic origin.