Absolute Configuration Determination of Chiral Compounds Using a Novel Crystalline Agent

手性酮是一类用途广泛的天然产物中间体，在萜类、信息素等生物活性化合物的结构中有着广泛的应用，但直接测定手性酮绝对构型的研究却很少。X射线晶体学分析是确定分子绝对构型的唯一方法。重原子的反常色散效应是确定绝对构型的必要条件。众所周知，肼是酮的良好结晶剂。因此，使用具有卤素原子的苯肼衍生物作为结晶剂。设计合成了几种肼类手性酮的结晶剂，发现2-氯-4，6-二硝基苯肼是一种很好的手性酮的结晶剂。2-氯-4，6-二硝基苯胺是一种弱碱，因为有两个硝基和一个氯原子，所以重氮化反应不会发生在一个转化反应中。 关于我们 理性的方式。苯胺溶于热醋酸中，用亚硝酸钠和硫酸制得的亚硝酰硫酸盐重氮化，再用碘化钾碘化得1-氯-2-碘-3，5-二硝基苯。将其与一水合肼在甲醇中在室温下搅拌，得到所需的肼。肼和手性酮的反应给出了适合于X射线晶体学分析的单晶。利用氯原子的反常色散效应确定了相应腙的晶体结构和绝对构型。通过Flack参数和Bijvoet对的强度比较成功地确定了它们的绝对构型。这是一种简单、直接的方法，并清楚地表明了这种方法的潜力。2-氯-4，6-二硝基苯肼是一种有用的晶体试剂，可用于绝对构型的测定。该方法适用于萜类和信息素类化合物，有助于确定各种手性酮的绝对构型。少

Chiral ketones are versatile intermediates of natural products and seen in the structure of biologically active compounds such as terpenes, pheromones, and so on. However, few studies are found in the literature for the direct method to determine the absolute configurations of these chiral ketones. X-Ray crystallographic analysis is the only method to determine the absolute configuration of a molecule. The anomalous dispersion effect of a heavy atom must be used for the determination of the absolute configuration. Hydrazines are well-known to be good crystalline agents for ketones. Thus, a phenylhydrazine derivative having a halogen atom is employed as a crystalline agent. We designed and synthesized some hydrazines as crystalline agents, and found that 2-chloro-4,6-dinitrophenyihydrazine is the useful crystalline agent for various chiral ketones. 2-Chooro-4,6-dinitroaniline is a weak base because of two nitro groups and a chlorine atom, so that diazotization does not occur with a conv … More entional way. Therefore, the aniline dissolved in hot acetic add was diazotized with nitrosyl sulfate prepared from sodium nitrite and sulfuric acid, and iodinated with potassium iodide to afford 1-chloro-2-iodo-3,5-dinitrobenzene. It was stirred with hydrazine monohydrate in methanol at room temperature to give the desired hydrazine. The reaction of the hydrazine and a chiral ketone gave the single crystal suitable for X-ray crystallographic analysis. The crystal structure and absolute configuration of the corresponding hydrazone was determined using the anomalous dispersion effect of a chlorine atom. The absolute configurations were successfully determined by Flack parameter and intensities comparison of Bijvoet pairs. This is the simple and direct method and the potential of this methodology was clearly demonstrated. 2-Chloro-4,6-dinitrophenylhdrazine is a useful crystalline agent for the absolute configuration determination. This method can be applied to terpenes and pheromones, and is helpful for the determination of the absolute configuration of various chiral ketones. Less