The reported structure of the natural calafianin (1) and its isomer in the epoxide region 13 were successfully synthesized through the cis- and trans-spiroisoxazoline compounds, which were produced by electrochemical oxidation of the hydroxyimino-phenol derivative 7, followed by Zn[BH4]2 reduction. Comparison of the spectroscopic data of the synthetic (±)-1 and (±)-13 resulted in structural revision of the natural calafianin to 13, possessing the trans-relationship between an epoxide and an oxygen of the isoxazoline. In addition, a significant difference of antimicrobial activity between 1 and 13 is discussed.
Effects of Aromatic Substituents of Electrochemically Generated Hypervalent Iodine Oxidant on Oxidation Reactions
作者:Shigeru Nishiyama、Yoshiharu Amano
DOI:10.3987/com-08-11331
日期:——
Phenolic oxidation of 4-hydroxyphenylpropionic acid (5) with electrochemically generated hypervalent iodine oxidant, was performed using a variety of iodobenzene derivatives. Iodobenzene derivatives carrying electron-deficient aromatic moieties showed oxidant activity comparable to that of bis(2,2,2-trifluoroethoxy)phenyliodine(III) 1, and better than those carrying electron-donating groups with the
Intramolecular cyclisation of phenolic oximes. Part II. Cyclisations with brominating agents
作者:Alexander R. Forrester、Ronald H. Thomson、Soo-On Woo
DOI:10.1039/p19750002348
日期:——
Intramolecularcyclisation of p-hydroxyarylpropan-2-one oximes to 2,5-dienonespiroisoxazolines can be achieved by using bromine, N-bromosuccinimide, or tetrabromocyclohexa-2,5-dienone. With an analogous ortho-phenolic oxime only the last of these was effective, the structure of the 2,4-dienonespiroisoxazoline formed being confirmed by an independent synthesis.
Synthesis and structural revision of calafianin, a member of the spiroisoxazole family isolated from the marine sponge, Aplysina gerardogreeni
作者:Takahisa Ogamino、Shigeru Nishiyama
DOI:10.1016/j.tetlet.2004.12.084
日期:2005.2
Calafianin I was successfully synthesized by employing a spiroisoxazoline compound, which was produced by electrochemical oxidation of the oximino-phenol derivative 7 followed by reduction. This investigation revealed a structural revision of 1, the trans-relationship of two oxygen atoms between the epoxide and the isoxazoline. (C) 2004 Elsevier Ltd. All rights reserved.
Kacan, Mesut; Koyuncu, Demet; McKillop, Alexander, Journal of the Chemical Society. Perkin transactions I, 1993, # 15, p. 1771 - 1776
作者:Kacan, Mesut、Koyuncu, Demet、McKillop, Alexander