The crystal structure of 10-(2′-pyridyl)pyrido[3,2-b][1,4]benzothiazine, 6, shows that orientation of the 10-pyridyl ring is in the plane bisecting the pyridobenzothiazine ring. This orientation is in contrast to that of 10-(2′-pyridyl)phenothiazine, 11, in which the heterocyclic ring is perpendicular to the plane bisecting the phenothiazine nucleus. X-ray data also indicate that the resonance interaction between the lone pair of electrons of NSUB10 in 6 with either the pyridine protons of the tricylcic ring or the 10-(2′-pyridyl) ring is not significant. The folding angle of 166.1° in 6 is the largest observed for the pyridobenzothiazine ring. The nmr spectral assignments of the titled compound, 6, was accomplished using the structurally similar, 10-phenylpyrido[3,2-b][1,4]benzothiazine, 9, as the model compound. 10-(2′-Pyridyl)phenothiazine, 11, was shown to be an inadequate model for such assigments.

中文翻译：

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10-（2'-吡啶基）吡啶并[3,2- b ] [1,4]苯并噻嗪的分子结构和¹³ C化学位移的定义为10-苯基吡啶并[3,2 - b ] [1,4]苯并噻嗪模型化合物

10-（2'-吡啶基）吡啶并[3,2-b] [1,4]苯并噻嗪的晶体结构6表明，10-吡啶环的取向在将吡啶并苯并噻嗪环平分的平面中。该取向与10-（2'-吡啶基）吩噻嗪11的取向相反，在10-（2'-吡啶基）吩噻嗪11中，杂环垂直于将吩噻嗪核平分的平面。X射线数据还表明，孤对NSUB10的电子在之间的共振相互作用6与任一tricylcic环的吡啶质子或10-（2'-吡啶基）环不是显著。在6中的166.1°折叠角是对吡啶并苯并噻嗪环观察到的最大折叠角。标题化合物的nmr光谱分配6使用结构相似的10-苯基吡啶并[3,2-b] [1,4]苯并噻嗪9作为模型化合物可完成。10-（2'-吡啶基）吩噻嗪（11）被证明不足以进行此类评估。