The structures of the novel triazolobenzothiazines 2,4-dihydro-1H-benzo[b][1,2,4]triazolo[4,3-d][1,4]thiazin-1-one (IDPH-791), C9H7N3OS, (I), a potential muscle relaxant, its benzoyl derivative, 2-(2-oxo-2-phenylethyl)-2,4-dihydro-1H-benzo[b][1,2,4]triazolo[4,3-d][1,4]thiazin-1-one, C20H17N3O4S, (II), and the β-keto ester derivative, ethyl 3-oxo-2-(1-oxo-2,4-dihydro-1H-benzo[b][1,2,4]triazolo[4,3-d][1,4]thiazin-2-yl)-3-phenylpropanoate, C17H13N3O2S, (III), are the first examples of benzothiazine-fused triazoles in the crystallographic literature. The heterocyclic thiazine rings in all three structures adopt a distorted half-chair conformation. Compound (III) exists in thetrans-β-diketo form. Other than N—H...O hydrogen bonds in (I) forming dimers, no formal intermolecular hydrogen bonds are involved in the crystal packing of any of the three structures, which is dominated by C—H...O/N and π–π stacking interactions.
新型三唑并噻嗪类化合物 2,4-二氢-1H-苯并[b][1,2,4]三唑并[4,3-d][1,4]噻嗪-1-酮(IDPH-791),C9H7N3OS,(I)的结构、一种潜在的肌肉松弛剂,其苯甲酰衍生物,2-(2-氧代-2-苯基乙基)-2,4-二氢-1H-苯并[b][1,2,4]三唑并[4,3-d][1,4]噻嗪-1-酮、C20H17N3O4S,(II) 和 β-酮酯衍生物,3-氧代-2-(1-氧代-2,4-二氢-1H-苯并[b][1,2,4]三唑并[4,3-d][1,4]噻嗪-2-基)-3-苯基丙酸乙酯,C17H13N3O2S,(III) 是晶体学文献中首个苯并噻嗪融合三唑的实例。这三种结构中的杂环噻嗪环都采用了扭曲的半椅构象。化合物 (III) 以反式-β-二酮形式存在。除了在 (I) 中形成二聚体的 N-H...O 氢键外,这三种结构的晶体堆积中都没有正式的分子间氢键,主要是 C-H...O/N 和 π-π 堆积相互作用。