Unprecedented Ring Contractions in Cytochalasans: Formation of [10]cytochalasans and a cyclohepta[4,5]benz[1,2-<i>d</i>]isoindole derivative
作者:Markus Boutellier、Werner Zürcher、Christoph Tamm
DOI:10.1002/hlca.19950780203
日期:1995.3.22
was converted to the chlorosulfinate 18 under the same conditions. Replacement of pyridine by triethylamine in the mesylation reaction led to the cyclohepta[4,5]benz[1,2-d]isoindole derivative 20, also representing a novel ring system.
进行了一系列细胞松弛素D(1;合子孢菌素A)的转化。在用甲磺酰氯和吡啶处理二醇7后,随后在硅胶上进行色谱分离,获得了17-乙酰基衍生物12和13,这是迄今未知的[10]细胞松弛素的第一个成员。在相同条件下,将醇8转化为氯亚磺酸盐18。在甲磺酰化反应中用三乙胺取代吡啶导致了环庚[4,5]苯并[1,2- d ]异吲哚衍生物20,也代表了一种新型的环系统。
Zygosporin D and Two New Cytochalasins Produced by the Fungus <i>Metarrhizium anisopliae</i>
Zygosporin D (3) and two new cytochalasins (4 and 5) were isolated from the culture filtrate of the fungus Metarrhizium anisopliae and characterized on the basis of their spectral data and chemical conversions. The new cytochalasins, 4 and 5, were determined to be deacetylcytochalasin C and (6R,16S,18R,2LR)-18,21-dihydroxy-16,18-dimethyl-10-phenyl[11]cytochalasa-13(E),19(E)-diene-1,7,17-trione, respectively. Of these three cytochalasins, only zygosporin D is an effective inhibitor of shoot elongation of rice seedlings.
Selektive Reaktionen an Cytochalasin D
作者:Georges Chappuis、Christoph Tamm
DOI:10.1002/hlca.19820650210
日期:1982.3.17
In connection with the total synthesis of cytochalasans the cleavage of the macrocyclic system of cytochalasin D (3) was studied in order to gain useful relay compounds. Selective scission of the double bond in 19-position was achieved by controlled ozonolysis leading to compound 7 (Scheme 1). Treatment of 3 with OsO4 and subsequent acetylation gave the tetraacetoxy- and diacetoxy derivatives 8 and