光化学法合成2-羟基咔唑

2-羟基咔唑是一种重要的有机中间体.但其合成方法尚报道不多,且存在制备过程较繁琐,反应步骤较多,收率普遍较低,成本较高等问题.确立了以邻氯苯胺和间苯二酚缩合而得的2-氯-3′-羟基二苯胺为原料,采用光化学方法,分子内环化,得到目标产物2-羟基咔唑.考察了不同光源、反应时间、碱和溶剂等因素对环合反应的影响.得到了在紫外灯照射下,三水合磷酸钾为碱,甲醇为溶剂合成2-羟基咔唑的较优的工艺条件,收率提高为51.6%6.产品经~1H-NMR确认.

A photochemical synthesis of 2-hydroxycarbazole

2-Hydroxycarbazole belongs to an important class of organic intermediates.However, there are few reports of its synthesis and several shortcomings such as complicated preparation processes,too many reaction steps,low yield,high cost and so on.A simple and efficient procedure for 2-hydroxycarbazole was synthesized by photocatalytic intramolecular cyclization of 3-(2-chlorophenylamino) phenol which was prepared from 2-chloroaniline and 1,3-benzenediol. The effect of different light,reaction times,bases,solvents on the reaction was examined.The optimum 2-hydroxycarbazole synthetic conditions which was illuminated in the light of ultraviolet lamp,potassium phosphate as a base,methanol as a solvent was obtained.The yield of final product was increased to 51.6%and the final product was confirmed by ~1H-NMR,