BACTERIAL STEROL SURROGATES - DETERMINATION OF THE ABSOLUTE-CONFIGURATION OF BACTERIOHOPANETETROL SIDE-CHAIN BY HEMISYNTHESIS OF ITS DIASTEREOISOMERS
BACTERIAL STEROL SURROGATES - DETERMINATION OF THE ABSOLUTE-CONFIGURATION OF BACTERIOHOPANETETROL SIDE-CHAIN BY HEMISYNTHESIS OF ITS DIASTEREOISOMERS
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DOI：
10.1021/jo00273a034
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发表时间：
1989-06-09
影响因子：
3.6
通讯作者：
ROHMER, M
中科院分区：
文献类型：
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作者：
BISSERET, P;ROHMER, M
Bacteriohopanetetrol（2a）具有在所有主要的原核三萜中遇到的C5多羟基化单元。3 4直到最近，这个单位的三个不对称中心的绝对配置仍然未知。从紫色细菌Rhodoparticulophiacidophila中分离出的腺苷藿烷（3）与细菌藿烷四醇（2a）4 h的化学相关性支持C-32，C-33和C-34的构型类似于D-核糖通过其末端C-5碳原子连接到藿烷骨架上所产生的构型，即32 fi，33 fi，和34 S。为了确定许多类霍帕烷的这一重要结构特征的构型，我们决定制备八种不同的细菌霍帕烷四醇侧链双立体异构体。与受保护的异戊糖的直接缩合已用于guggultetrols 5的合成和甲氨蝶呤的四羟基戊烷部分的制备。6我们已经发现，在C-30处与藿烷骨架的这种连接作用价值有限，可以有利地用方案II中概述的逐步构造来代替。
Bacteriohopanetetrol (2a) possess the C5 polyhydroxylated unit encountered in all major prokaryotic triterpenoids. 3 4 Until recently, the absolute configuration of the three asymmetric centers of this unit remained unknown. The chemical correlation of adenosylhopane (3) isolatedfrom the purple bacterium Rhodopseudomonas acidophila with bacteriohopanetetrol (2a) 4h supported a configuration in C-32, C-33, and C-34 similar to the one resulting from the attachment of a D-ribose through its terminal C-5 carbon atom to the hopane skeleton, ie 32fi, 33fi, and 34S.To establish the configuration of this important struc-tural feature of many hopanoids, we decided to prepare the eight different bacteriohopanetetrol side chain dia-stereomers. A direct condensation with a protected aldehydo-pentose has been employed in the synthesis of guggultetrols5 and in the elaboration of the tetra-hydroxypentane portion of methanopterin. 6 Wehave found that such a linkage to the hopane skeleton at C-30 was of limited value and could be advantageously replaced by a step-by-step construction outlined in Scheme II.