The synthesis of various cycloalkana[d]xanthones and conversion of the cyclohexa-analogue to a 7,7a-dimethylcyclohexa[d]xanthene
The synthesis of various cycloalkana[d]xanthones and conversion of the cyclohexa-analogue to a 7,7a-dimethylcyclohexa[d]xanthene
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DOI：
10.1039/a804365e
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发表时间：
1998-10-07
期刊：
影响因子：
--
通讯作者：
Cheung, KK
中科院分区：
文献类型：
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作者：
Letcher, RM;Yue, TY;Cheung, KK
描述了由(E)-(2-羟基苯基)-5-芳基戊-4-烯-1,3-二酮4、环烷酮和吡咯烷合成环五-、-六-和-七-[d]呫吨酮5。还描述了试图合成五种天然存在的环己[d]呫吨（通式 1）的类似物时对 5 进行修饰的反应：这些反应包括 C-7 和 C-7a 处的 C-甲基化、8-酮基的氢化物还原、脱羟基和最终催化还原得到 16。通过 NOE 和 9aB 的 X 射线晶体结构建立的 16 的立体化学与 1 的不同之处在于 2连续的 C 原子。
The synthesis of cyclo-penta-, -hexa- and -hepta-[d]xanthones 5 from (E)-(2-hydroxyphenyl)-5-arylpent-4-ene-1,3-diones 4, cycloalkanones and pyrrolidine is described. Reactions to modify 5 in an attempt to synthesize analogues of the five naturally occurring cyclohexa[d]xanthenes (with general formula 1) are also described: these reactions include C-methylations at C-7 and C-7a, hydride reduction of the 8-keto group, dehydroxylations and finally catalytic reduction to give 16. The stereochemistry of 16 established by NOE and an X-ray crystal structure of 9aB differs from 1 at two contiguous C-atoms.