二螺[5.1.5.3]化合物立体结构的研究

Study on the structure of dispiro [5. 1 .5.3] compounds

２，１０－二（β乙氧羰基）－３，１１－二羟基－二螺［５．１．５．３］十六－２，１０－二烯－７－酮不同熔点的光学异构体的构型一直未确定，本文利用化学方法、核磁共振法和Ｘ－射线晶体衍射法，确定了这两个不同熔点的异构体的相对构型及其在溶液和晶体中的构象。为了研究二螺［５．１．５．３．］类化合物的结构问题，首先合成了一系列的二螺［５．１．５．３］化合物，对它们的化学性质进行研究，其中６个是未见文献报道的新化合物。然后用二维核磁共振方法研究２，１０－二（β－乙氧羰基）－３，１１－二羟基－二螺［５．１．５．３］十六－２，１０－二分７－酮的异构体，确定了它们的相对构型，具有 １４Ｄ～１４１℃熔点的为内消旅（Ｒ， Ｓ）构型。而具８２～３８℃熔点的为由（Ｒ，Ｒ）和（Ｓ，Ｓ）构型组成的外消旋体；通过对二维核磁共振谱的分析，讨论了这两个二螺环化合物在溶液中的构象。同时培养得到了其中具有８２～８３℃熔点的２，１０－二（β－乙氧羰基）－３，１１－二羟基－二螺［５．１．５．３］十六－２，１０－二烯－７－二的片状单晶，用Ｘ－衍射线射法测定了它的晶体结构，空间群为Ｐｎｃａ，发现其晶体在一维具有很大晶胞参数，在有机小分子晶体中比较少见。

di (β-carboxyethyl) -3, 11-dihydroxy-dispiro[5.1.5. 3]hexadecan- 2, 10-dien-7-one was synthesized in 1950s, but the relative configurations of the two isomeric products with different melting points have never been determined. In this paper, the two isomeric products were studied with chemical methods, nuclear magnetic resonance spectroscopy and X-ray diffractional methods. It can be concluded that the isomer with the melting point of 140-141℃is a meso compound of (R, S) configuration, while the other with the melting point of 82-83℃ is a racemate consisted of compounds of (R, R) and (S, S) configurations. After studying the COSY and NOESY spectrum of the two dispiro compounds, the authors analysized their conformations in solution. At the same time, the crystal structure of low melting point compound, a single crystal of the 10- 2, di (gβ-carboxyethyl) -3, 11-dihydroxy -dispiro [5.1.5.3] hexadecan-2, 10-dien-7-one, was determined.