4-氯-1,7-二羟基二氢化茚的合成及意外醚化反应的研究

以对氯苯酚(8)为原料、三乙胺作缚酸剂，与丙烯酰氯反应生成对氯苯酚丙烯 酸酯(7)，7与A1Ck共热155℃，首先发生Fries重排，然后关环得到4-氯-7-羟基二 氢化茚-1-酮(6)，再用NaBHl／CH_3OH或LiAlH_4／THF还原6的羰基得到4-氯-1，7- 二羟基二氢化茚(5)．条件控制不当易产生两个意外的醚化产物4-氯-1-甲氧基-7- 羟基二氢化茚(9)和自身醚化产物10，9的结构经x射线单晶衍射分析确证，并提出 生成10的可能机理为5的醇羟基极易通过分子内催化形成碳正离子、进而与另一分 子5形成自身醚化产物10．因此，还原反应完成后的后处理应避免长时间放置和加 热，以减少醚化产物的生成．化合物5，9，10均为未见文献报道的新化合物．

Study on the Synthesis and Unexpected Etherification of 4-ChIoro- indan-l,7-diol

4-Chlorophenol (8) reacted with acryloyl chloride in the presence of Et_3N as acid scavenger to give acrylic acid 4-chlorophenyl ester (7). Compound 7 was heated at 155~°C with A1C1_3 to undergo Fries rearrangement and ring closure affording 4-chloro-7-hydroxy-indan-l- one (6) . Reduction of the carbonyl group of 6 with NaBH_4/CH_3OH or LiAlH_4/THF gave 4-chloro-indan-l,7-diol (5). Two unexpected ethers (methyl etherified product 9 and dimerized ether 10) were formed in this reduction if the workup procedure is not controlled carefully. The structure of 9 was determined by X-ray diffraction analysis and the mechanism of etherification was proposed. 1-Hydroxy group of 5 is easy to form its ether derivative 10 through an intramolecular catalysis of carbon cation formation, followed by the reaction with compound 5 itself. Therefore, the workup of the reaction mixture and separation of product 5 should be done as soon as possible after the reduction was completed in order to prevent the formation of ether byproducts. New compounds 5, 9 and 10 were characterized by ~1H NMR, ~13C NMR, MS and elemental analysis or HRMS.