SYNTHESIS AND STRUCTURAL-PROPERTIES OF THE BENZOPENTATHIEPINS VARACIN AND ISOLISSOCLINOTOXIN-A
SYNTHESIS AND STRUCTURAL-PROPERTIES OF THE BENZOPENTATHIEPINS VARACIN AND ISOLISSOCLINOTOXIN-A
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DOI：
10.1021/jo00099a026
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发表时间：
1994-10-07
影响因子：
3.6
通讯作者：
DAVIDSON, BS
中科院分区：
文献类型：
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作者：
FORD, PW;NARBUT, MR;DAVIDSON, BS
独特的含五噻吩化合物 Varacin (1) 和 isolissoclinotoxin A (3) 均由香草醛经过八个步骤合成。通过用 2 当量的 S2Cl2 处理二硫醇根阴离子（由二丁基硫醚中间体 10 的 Na/NH3 还原产生），完成了五硫苯哌啶环在伐拉辛中的形成。通过在吡啶/喹啉中于 160 摄氏度下用正丁基硫醇亚铜处理 5,6-二溴香草醛 (6)，将硫原子放置在芳环上。通过 X 射线衍射分析证实了倒数第二个中间体 TEOC 保护的伐拉辛 (II) 的结构。 Isolissoclinotoxin A 以类似的方式制备，使用 MOM 基团来保护苯酚。伐拉辛的结构已被证实；然而，3 的还原乙酰化产生了四乙酸酯衍生物 20，这与报道的 lissoclinotoxin A 乙酰化产物不同。由于 20 记录的数据与之前报道的数据不符，因此 lissoclinotoxin A 的结构可能应重新分配给区域异构体 4，其中苯酚和甲氧基互换。
The unique pentathiepin-containing compounds varacin (1) and isolissoclinotoxin A (3) have each been synthesized in eight steps from vanillin. Formation of the pentathiepin ring in varacin was accomplished by treatment of the dithiolate anion, generated from the Na/NH3 reduction of bisbutyl sulfide intermediate 10, with 2 equiv of S2Cl2. Placement of the sulfur atoms on the aromatic ring was accomplished by treatment of 5,6-dibromovanillin (6) with cuprous n-butylmercaptide in pyridine/quinoline at 160 degrees C. The structure of the penultimate intermediate, TEOC-protected varacin (II), was confirmed by X-ray diffraction analysis. Isolissoclinotoxin A was prepared in an analogous manner, using a MOM group to protect the phenol. The structure of varacin has been confirmed; however, reductive acetylation of 3 yielded tetraacetate derivative 20, which was different than that reported as a product of lissoclinotoxin A acetylation. Because the data recorded for 20 did not match that previously reported, it is likely that the structure of lissoclinotoxin A should be reassigned to regioisomer 4, which has the phenol and methoxy group interchanged.