Pyridines from marine organisms

The sex attractant of the sea slug Navanax inermis contains pyridine bases, one of which is the 3-pyridyltetraenone (140) (H.L. Sleeper and W. Fenical, J.Amer.chem.Soc., 1977, 99, 2367). Another structure, perhaps of vegetable origin, is pulo upone (153) which has been isolated as a trace constituent of the Hawaiian mollusc Philinopsis speciosa (S.J. Coval et al., Tetrahedron Letters, 1985, 26, 5359). 

Known quinolines from micro-organisms and higher plants 

Since the main work (C.C.C. 2nd edn., Vol.lVG, Ch.31. pp 171-255) was written interest in this group of natural products has continued apace. Many new alkaloids have been Isolated and their structures determined principally by H-and C-n.m.r. spectroscopy, and by part syntheses from known alkaloids. In addition new plants of the Rutacea family have been examined and found to contain familiar structures. A measure of this latter activity is provided by the Tables 1 - 6 in which extractives of established structure present in these plants are listed. 

RUTACEOUS ALKALOIDS OF ESTABLISHED STRUCTURE (see the main work for details) 

Flindersine Atlantia, Fagara, ° Haplophyllum, Micromelura,Zanthoxyllum ° 

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Niphatoxin A (33) and B (34). Two ichthyotoxic alkaloids, niphatoxin A (33) and B (34), containing interconnected pyridinium and pyridine rings, were isolat from Niphates sp. These compoimds are the first examples of tripyridine alkaloids found in marine organisms [35]. The structures of these compounds were deduced by intensive NMR (COSY, TOCSY, HMQC and HMBC) work and mass spectrometry. 

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