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Caulerpenyne‐Amine Reacting System as a Model for in vivo Interactions of Ecotoxicologically Relevant Sesquiterpenoids of the mediterranean‐adapted tropical green seaweed caulerpa taxifolia
Author(s) -
Guerriero Antonio,
Depentori Daniela,
D'Ambrosio Michele,
Pietra Francesco
Publication year - 1995
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19950780709
Subject(s) - chemistry , isomerization , stereochemistry , amine gas treating , pyridine , pyrrole , medicinal chemistry , organic chemistry , catalysis
Caulerpenyne ( 1 ), the most abundant of the ecotoxicologically relevant sesquiterpenoids of the Mediterranean‐adapted tropical green seaweed Caulerpa taxifolia , was found to react with Et 3 N or pyridine in MeOH by initial deprotection of C(1)HO to give oxytoxin 1 ( 2a ), previously isolated from the sacoglossan mollusc Oxynoe olivacea . With BuNH 2 , without any precaution to exclude light, 1 gave the series of racemic 3 and 4 , and achiral (4 E ,6 E )‐ 5 , (4 E ,6 Z )‐ 5 , (4 Z ,6 E )‐ 5 , and (4 Z ,6 Z )‐ 5 pyrrole compounds, corresponding to formal C(4) substitution, 4,5‐β‐elimination, and ( E/Z )‐isomerization at the C(4)C(5) and C(6)C(7) bonds. Changing to CDCl 3 as solvent in the dark, 1 gave cleanly, via 2a as an intermediate, 3 and (4 E ,6 E )‐ 5 . The latter proved to be prone to ( E/Z )‐photoisomerization. Under standard acetylation conditions, 3 gave (4 E ,6 E )‐ 5 via acetamide 7 as an intermediate. Particular notice is warranted by selective deprotection of 1 at C(1), mimicking enzyme reactions, and unprecedented formation of pyrrole compounds from freely‐rotating, protected 1,4‐dialdehyde systems.