一种苯并噻唑类稳定烯醇的合成及晶体结构

以2-甲基苯并噻唑和1,3-丙磺酸内酯为起始原料,合成了一种菁染料中间体2-(2-乙氧基-1-丁烯基)-1-(3-磺酸丙基)苯并噻唑(3).该染料中间体极易水解,对其水解产物(4e)采用红外光谱、核磁共振、质谱、元素分析和X射线单晶衍射分析等方法进行了表征.MS结果显示水解产物4e的分子量为327;在13C NMR谱图中,烯醇结构中与羟基相连的碳的化学位移为194.05,与之相连的另一个双键碳的化学位移为δ92.52;在IR谱图中,1618 cm-1处存在烯醇的特征吸收峰;通过X射线单晶衍射分析测定了水解产物的结构,进一步证实该水解产物是一种存在共轭芳基结构的稳定烯醇.

Synthesis and Crystal Structure of Stable Benzothiazole Enol

As an important organic functional compound, 2-methylbenzothiazole derivatives has been widely used in sensitizing dyes. In the process of sythesis of dyes, the dye intermediates could be hydrolyzed to form another substance easily. In order to determine the structure of the new substance, a dye intermediate, named 2-(2-ethoxy-1-butenyl)-1-(3-sulfopropyl)benzothiazole(3), was synthesized using 2-methyl benzothiazole and 1,3-propane sultone as the starting material, then hydrolyzed in water to form the new substance(4e), which was characterized by IR, 1H NMR, 13C NMR, MS, elemental analysis and X-ray diffraction methods. The MS spectrum showed the molecular weight of the product was 327, which was corresponding to the target compound 4e. The 13C NMR spectrum showed the chemical shift of the carbon that connected to the enol hydroxyl group was δ 194.05, and the chemical shift of the carbon that connected to the double bond was 92.52, which implied the existence of enol structure. The IR spectrum also showed the enol hydroxyl characteristic absorption peak at 1618 cm-1. X-Ray diffraction displayed the structure of the target compound intuitively. Through the characterizations of the compound, the new substance was comfirmed to be a stable enol that contained the conjugated aromatic structure.