聚乙二醇用作改善亲核取代反应的相转移催化剂

Polyethylene Glycol(PEG) as Phase Transfer Catalyst for Improvement of Nucleophilic Substitution on Ring A of Bromoestrogen to Methoxyestrogen

研究了将聚乙二醇用作相转移催化剂及其对亲核取代反应的改善．先将雌二醇经溴化制得２或４溴雌二醇，再分别在氯仿中以聚乙二醇（ＰＥＧ４００）作相转移催化剂（ＰＴＣ）进行亲核取代反应制备２或４甲氧基雌二醇．发现其适宜条件为：反应温度６０～６５℃，搅拌反应时间１．５ｈ，试剂比例底物为甲醇ＫＯＨＰＥＧ＝１２０８００．８，获得较高亲核取代产率：２甲氧基雌二醇６６．７％及４甲氧基雌二醇７０．３％，结果良好，操作简便．

Polyethylene Glycol(PEG)is studied to be used as phase transfer catalyst (PTC) for organic synthesis. In this paper,nucleophilic substitution of 2 or 4 bromoestrogen,prepared from estradiol,by bromination with N bromosuccinimide(NBS),to 2 or 4 methoxyestogen by methoxidion with methanot,,was catalysed by the PTC,PEG 400 .The proper experimental conditions are found to be:chloroform as solvent,reaction temperature being 60～65 ℃, stirring reaction time being 1.5 h,regent ratio being bromoestrogenMeOHKOHPEG=120800.8. The yields of nucleophilic substitution reaction are 66.7% and 70.3% for 2 and 4 methoxyestrogens,respectively.