Synthesis and Structural Characterization of Cis- and Trans-Fused 4a,5,6,7,8,8a-Hexahydro-2<i>H</i>,4<i>H</i>-1,3-benzodithiines and Their 2-Methyl and 2,2-Dimethyl Derivatives
作者:Kalevi Pihlaja、Karel D. Klika、Jari Sinkkonen、Vladimir V. Ovcharenko、Olga Maloshitskaya、Reijo Sillanpää、József Czombos
DOI:10.1021/jo011021u
日期:2002.3.1
Both cis- and trans-fused 4a,5,6,7,8,8a-hexahydro-2H,4H-1,3-benzodithiine together with their 2-methyl and 2,2-dimethyl derivatives were prepared as racemates from the appropriate dithiols obtained via multistep syntheses. The products were characterized by (1)H and (13)C NMR, mass spectrometry, and for two of the cis-fused compounds by X-ray diffraction. (1)H,(1)H vicinal coupling constants indicated
顺式和反式融合的4a,5,6,7,8,8a-六氢-2H,4H-1,3-苯并二乙胺以及它们的2-甲基和2,2-二甲基衍生物均由适当的化合物制成外消旋体通过多步合成获得的二硫醇。通过(1)H和(13)C NMR,质谱对产物进行表征,并且通过X射线衍射对两种顺式稠合化合物进行表征。(1)H,(1)H邻位偶合常数表明,所有化合物均以椅子-椅子构象为主要构象。所有这三种反式-融合异构体均以完全偏向的椅子-椅子构象存在,并且基本上在构象上被锁定,而顺式融合的化合物在构象上可移动,并且可能获得S-in或S-out构象。在环境温度下,构象异构体的互变在NMR时间尺度上很快,但在213 K 4ar,5时,6,7,8,8ac-六氢-1,3-苯并二硫氨酸分别冻结成S-in和S-out形式的83:17混合物。2c-甲基-4ar,5,6,7,8,8ac-六氢-1,3-二硫氨酸和二甲基衍生物在环境温度下几乎都采用S-