Synthesis and stereochemistry of Δ<sup>2,2′</sup>-bi-(2H-1,4-benzothiazine) derivatives. Crystal structures of cis- and trans-Δ<sup>2,2′</sup>-bi-(3-p-bromophenyl-2H-1,4-benzothiazine)
作者:F. Giordano、L. Mazzarella、G. Prota、C. Santacroce、D. Sica
DOI:10.1039/j39710002610
日期:——
isomers has been explained in terms of the molecular structures of the cis- and trans- isomers of the 3-p-bromophenyl derivative (IIa) which were determined by three-dimensional X-ray analysis. The cis-isomer crystallizes in space group P, with Z= 2, in a unit cell of dimensions a= 10·18, b= 12·90, c= 10·65 Å, α= 113° 56′, β= 95° 57′, γ= 103° 5′. Crystals of the trans-isomer are monoclinic, space group
Δ 2,2' -Bi-(2 ħ -1,4-苯并噻嗪)衍生物(II)制备了相应的3-取代的2-氧化ħ -1,4-苯并噻嗪(I)通过使用氯醌作为脱氢代理人。该反应提供了(II)的顺式和反式异构体,它们甚至在室温下也易于在溶液中相互转化。异构体的理化性质比较表明,尽管在3-和3'-位存在大量的取代基,但室温下的主要异构体仍具有顺式构型。几何异构体的相对稳定性已根据顺式和反式的分子结构进行了解释。通过三维X射线分析确定了3-对-溴苯基衍生物(IIa)的反式异构体。该顺式-异构体结晶,空间群P,与Ž = 2,在尺寸的单元电池一个= 10·18,b = 12·90,C ^ = 10·65埃,α= 113°56',β= 95 °57',γ= 103°5'。该晶体的反式-异构体是单斜晶系,空间群P 2 1 / ç与ž在尺寸的晶胞= 2,一个= 7·057,b = 12·70,Ç= 14·04Å,β= 10