羟甲基和碘甲基取代的3,4-亚乙基二氧噻吩衍生物及其选择性酯化与醚化

Synthesis of 3,4-Ethylenedioxythiophene Substituted with Hydroxymethyl and Iodomethyl Groups and Their Selective Esterification and Etherification

羟甲基或碘甲基取代的3,4-亚乙基二氧噻吩(EDOT)衍生物与含氰乙基或羧酸基的四硫代富瓦烯(TTF)衍生物通过酯化或醚化反应可生成EDOT-TTF类型的化合物.在此过程中发现,由3,4-二羟基噻吩-2,5-二羧酸甲酯(1)与环氧溴丙烷经醚化反应生成的关环产物是一个由3,4-二氧-羟甲基乙基噻吩-2,5-二羧酸甲酯(2)与3,4-二氧-2'-羟基亚丙基噻吩-2,5-二羧酸甲酯(2')组成的混合物,两者很难用常规手段分离.由(2+2')衍生的2,5-二羧酸甲酯-3,4-二氧-碘代甲基亚乙基噻吩(3)和3,4-二氧-碘代亚丙基噻吩-2,5-二羧酸甲酯(3')以及3,4-二氧-羟甲基亚乙基噻吩(4)与3,4-二氧-2'-羟基亚丙基噻吩(4')与2-氰乙基硫-3-甲基硫-6,7-二(正己基硫)-四硫代富瓦烯(TTF-1)或2-羧甲基硫-3-甲基硫-6,7-二(正己基硫)-四硫代富瓦烯(TTF-3)进行醚化或酯化反应表现出了高度的选择性,只有3能与TTF-1反应生成结构单一的EDOT-TTF 1.同样只有4能与TTF-3反应生成结构单一的EDOT-TTF 2.

3,4-Ethylenedioxythiophene （EDOT） and its derivatives contained hydroxyl groups are good blocks for the synthesis of the functional molecules based on EDOT. However, the products of the reaction between dimethyl 3,4-dihydroxy-thiophene-2,5-dicarboxylate （1） and epibromohydrin via Williamson etherification were a mixture of dimethyl 2＇-hydroxymethyl-3,4-ethylendioxy-thiophene-2,5-dicarboxylate （2） and dimethyl 2＇-hydroxypropyl-3,4-dioxythiophene- 2,5-dicarboxylate （2＇）, which is difficult to separate. Dimethyl 2＇-iodomethyl-3,4-ethylendioxy-thiophene-2,5-dicarboxylate （3） and dimethyl 2＇-iodopropyl-3,4-dioxythiophene-2,S-dicarboxylate （3＇） as well as 3,4-ethylendioxy-2＇-hydroxymethyl-thio- phene （4） and 3,4-dioxy-2＇-hydroxypropyl-thiophene （4＇） were synthesized by using the mixture. They are still mixtures and difficult to separate. It is very surprising that when an etherification reaction between the mixture （3＋3＇） and cyano- ethyl-carried tetrathiafulvalene （TTF-1） was conducted, the reaction showed highly selectivity, i.e., only 3 could react with TTF-1. The same situation happened when an esterification between the mixture （4＋4＇） and carboxylic acid carried tetrathia- fulvalene （TTF-3） was made, only 4 could react with TTF-3. Both the reactions afforded a single product, i.e., EDOT-TTF 1 and EDOT-TTF 2, respectively, whose chemical structures were characterized by 1H NMR, 13C NMR, MS, and HRMS.