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'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.
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Jiménez et al. (2000) studied this question.
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