N-7C-11 C-4C-12 Derivatives

This class of cyclic oroidin derivatives also parallels the above N-7/C-11 + N-1/ C-12 class in the presence of complex derivatives in which the isophakellin skeleton appears to be conjugated with an aminoimidazolyl propene unit. These isomers of palau amines are called styloguanidines (58-60) they have been isolated from the same sponge that contains palau amines, Stylotella aurantium [90]. 

These molecules were shown to be potent inhibitors of chitinase, an enzyme involved in the ecdysis of many insects and crustaceans, whose inhibitors are supposed to control the settlement of barnacles and, therefore, could have a potential application as antifouling agents. Unfortunately, no data are available in the literature about cytotoxic, immunosuppressive, or antibacterial activities of styloguanidines and, thus, a comparison with the potently bioactive congeners palau amines is not possible. 

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