Fixation of Natural Furanoeremophilane by Diels–Alder Reaction
作者:Kazunori Iida、Makoto Mitani、Chiaki Kuroda
DOI:10.1246/bcsj.80.966
日期:2007.5.15
Diels–Alder reaction of furanoeremophilan-6β-ol (petasalbin) and its synthetic analogue, 4-hydroxy-4,5,6,7-tetrahydrobenzofuran, was studied using N-ethyl- and N-phenylmaleimides as the dienophiles, affording corresponding adducts as mixtures of stereoisomers. The adduct of petasalbin and maleimide was also obtained when the latter compound was added to a crude extracted solution of Petasites japonicus var. giganteus. By using this method, it was estimated that the contents of unstable furanoeremophilan-10β-ol in L. cymbulifera is more than 32% of the extract.
对呋喃埃雷莫菲兰-6β-醇(petasalbin)及其合成类似物4-羟基-4,5,6,7-四氢苯并呋喃的Diels–Alder反应进行了研究,以N-乙基和N-苯基马来酰亚胺作为二烯亲核试剂,生成了相应的加成产物,形成了立体异构体的混合物。当将马来酰亚胺添加到宠物石竹(Petasites japonicus var. giganteus)的粗提取液中时,也获得了petasalbin与马来酰亚胺的加成产物。通过这种方法估计,在L. cymbulifera中的不稳定呋喃埃雷莫菲兰-10β-醇的含量超过提取物的32%。
Ehrlich’s Reaction of Furanoeremophilanes
作者:Chiaki Kuroda、Tadashi Ueshino、Hajime Nagano
DOI:10.1246/bcsj.77.1737
日期:2004.9
6-Ethoxyfuranoeremophilane and its synthetic analogue, 4-ethoxy-4,5,6,7-tetrahydrobenzofuran, reacted with p-dimethylaminobenzaldehyde (Ehrlich's reagent) under acidic conditions in a 2:1 ratio to afford condensation products in 34% and 78% yields, respectively, 6-Hydroxyfuranoeremophilane and 4-hydroxy-4,5,6,7-tetrahydrobenzofuran afforded the same products as in the case of ethoxy derivatives, respectively
Mass spectral fragmentations of furanoeremophilane derivatives bearing oxygen-function on B ring were investigated. It was found that massspectra measured by direct inlet system gave characteristic retro-Diels-Alder fragmentations, while indirect introduction of the samples afforded intense peaks at m/e 159 and m/e 145 containing the furan moiety. Fragmentation patterns of other poly-functional derivatives
研究了在 B 环上带有氧功能的呋喃埃勒姆衍生物的质谱碎裂。发现通过直接进样系统测量的质谱给出了特征性的逆狄尔斯-阿尔德碎片,而间接引入样品在含有呋喃部分的 m/e 159 和 m/e 145 处提供了强烈的峰。通过测量精确质量和亚稳态离子来检查其他多功能衍生物的碎片模式。
Bis heteroannulation. 3. Facile synthesis of (.+-.)-ligularone and (.+-.)-petasalbine
作者:Peter A. Jacobi、Donald G. Walker
DOI:10.1021/ja00405a067
日期:1981.7
Bis heteroannulation. 4. Facile syntheses of methylene acids, methylbutenolides, .alpha.-methyl-.gamma.-lactones, and related materials. Total syntheses of (.+-.)-ligularone and (.+-.)-petasalbine
作者:Peter A. Jacobi、Todd A. Craig、Donald G. Walker、Bradley A. Arrick、Roger F. Frechette