Photochemical Relationships in Sacoglossan Polypropionates

• Published in: Journal of natural products (Washington, D.C.) Vol. 68; no. 4; pp. 481 - 486
• Main Authors: Zuidema, Daniel R, Jones, Paul B
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 01.04.2005; Amer Chemical Soc; American Society of Pharmacognosy
• Subjects: Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Catalysis; Chemistry, Medicinal; cyercene; Fundamental and applied biological sciences. Psychology; Gastropoda; Heterocyclic compounds, pigments; Indicators and Reagents; Life Sciences & Biomedicine; Marine; Miscellaneous; Molecular Structure; Mollusca - chemistry; Nuclear Magnetic Resonance, Biomolecular; Other biological molecules; Oxidation-Reduction; Pharmacology & Pharmacy; photochemical reactions; Photochemistry; photooxidation; Placida dendritica; placidene; Plant Sciences; Propionates - chemistry; pyrones; Pyrones - chemical synthesis; Pyrones - chemistry; Rose Bengal; Sacoglossa; Science & Technology; Sunlight; DEFENSE; PLACIDENES; CYERCENES; PYRONES; BIOSYNTHESIS; Conjugated polyenic compound; Photoisomerization; Isomerization; Pyran derivatives; Animal origin; Hydroperoxide; Models; Photochemical reaction; Invertebrata; Mollusca; Pyranone derivatives
• ISSN: 0163-3864; 1520-6025
• DOI: 10.1021/np049607+

Cyercene A (7) has been synthesized and converted to placidene A (3) and isoplacidene A (8) through photoisomerization with sunlight. Hydroperoxide 4, isolated form Placida dendritica, was synthesized both by singlet oxygenation of cyercene A using Rose Bengal and through the irradiation of cyercene A alone in aerobic solution. The observation that hydroperoxide 4 could be made by singlet oxygenation of cyercene A and that this occurs when cyercene A alone is irradiated supported the hypothesis that γ-pyrones may act as triplet sensitizers. This was confirmed using cyercene A and a model γ-pyrone to sensitize the photooxidation of n-butyl sulfide. The biosynthetic implications of these observations for Sacoglossan polypropionates are discussed.