Polycitone alkaloids

A type Had cyclization of vinamidinium salt 24 with a-aminoacetophenone 25 in the presence of sodium hydride led to the formation of 2-keto-4-arylpyrrole 26 <05T1845>. The latter was utilized in a regiocontroUed preparation of the polycitone alkaloids. Vinamidinium salt 24 was readily available from phenylacetic acid 23 by a Vilsmeier-Haack type process. 

Rudi A, Evan T, Aknin M, Kashman Y (2000) Polycitone B and Prepolycitrin A Two Novel Alkaloids from the Marine Ascidian Polycitor africanus. J Nat Prod 63 832... 

As part of their ongoing investigation of bioactive natural products from tropical marine invertebrates collected in Sodwana Bay (situated in northern Kwazulu-Natal, South Africa), Kashman and co-workers isolated three novel alkaloids, polycitone A (89) and polycitrins A and B (90 and 91) from an ascidian Polycitor sp. [86]. The structure of 89 was established from X-ray data while the structures of 90 and its mono-O-methyl ether analogue, 91, followed from analysis of the NMR data of these two compounds. Two possible biosynthetic precursors of 89-91,... 

Rudi, A., Evan, T., Aknin, M., Kaslunan, Y., (2000). Polycitone B and Prepolycitrin A Two novel alkaloids from the marine ascidian Polycitor africanus. J. Nat. Prod. 63, 832-833. 

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