PubMed · 5487131
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N Narasimhachari, M B Swami. 1970. Dermostatin: a revised hexaene structure.. https://doi.org/10.7164/antibiotics.23.566
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The unsaturations and groups bound to the ring and to the lateral chain of lactones give a large diversity in this class of molecules. In this work we produced enzymatically a macrolactone in organic media. The substrate used was a hydroxy-fatty acid: (+)-coriolic acid and the enzymes tested were free or immobilized microbial lipases. The immobilized lipase from Candida antarctica seems to be the most adequate catalyst offering a high reaction yield. The intra-esterification was studied as a function of temperature and type of solvent. Higher yields were obtained when using diisopropyl-ether at 35 degrees C. This reaction, involving an alcohol group on an internal position on the carbon chain of the substrate hydroxy-acid, produces an original lactone: 13S-octadeca-(9Z,11E)-dienolide. The product was purified and characterized using (1)H nuclear magnetic resonance spectroscopy, mass spectrometry and infrared spectroscopy.
This article reports the transformation of O-acetylisophotosantonin, obtained by photochemical rearrangement of santonin, into plagiochiline N, an ent-2,3-secoaromadendrane isolated from Plagiochila ovalifolia. The synthesis was carried out in a sequence involving as the key steps (a) the substitution of the lactone moiety by a gem-dimethylcyclopropane ring through a synthetic intermediate having a C(6)-C(7) double bond and (b) the ozonolysis of the C(2)-C(3) bond followed by cyclization to the dihydropyran ring characteristic of plagiochiline N. Spectroscopic data of the synthetic product fully coincided with the reported data for the natural product.
Bioassay-directed fractionation of the EtOH extract of an Oceanapia sp. collected off the northern Rottnest Shelf, Australia, has yielded three novel dithiocyanates, thiocyanatins A (1), B (2a), and C (2b). The structures were determined by detailed spectroscopic analysis and confirmed by total synthesis. In addition to featuring an unprecedented dithiocyanate functionality, thiocyanatins possess an unusual 1,16-difunctionalized n-hexadecane carbon skeleton and are revealed as a hitherto unknown class of nematocidal agent.