The origin of the long range coupling in exocyclic epoxides with quasi-axial methylenes has been established by the synthesis of specifically deuterated analogues. Use was made of paramagnetic shift reagents in distinguishing between the epoxide protons.
This study synthesized 20 sclareol derivatives. The antifungal activities of these derivatives were evaluated in vitro against five phytopathogenic fungi using the mycelium growth rate method. Among all the tested compounds, compound 16 with one iodine atom and three hydroxyl groups displayed higher fungicidal activities against all the tested phytopathogenic fungi than precursor sclareol. Compound 16 also showed more pronounced antifungal activities against Curvularia lunata (IC50 = 12.09 mu g/mL) and Alternaria brassicae (IC50 = 14.47 mu g/mL) than the positive control, a commercial agricultural fungicide thiabendazole. (C) 2015 Elsevier Ltd. All rights reserved.
Prehispanolone Analogs: Stereochemistry Control at C-5 in the Preparation of 1-Oxaspiro[4,5]decane Fused Systems and Related Compounds
作者:Pilar Basabe、Antonio Estrella、Isidro S. Marcos、David Díez、Anna M. Lithgow、A. J. P. White、David J. Williams、Julio G. Urones
DOI:10.1055/s-2001-9723
日期:——
A new strategy for acid-catalyzed intramolecular epoxide ring-opening is described for preparing grindelic acid derivatives. Proper functionalization of ring B allows stereochemical control for the epoxide and spiran carbons. The carbonyl group at C-7 allows the control of C-8 in the synthesis of prehispanolone analogues.