论文部分内容阅读
在有机合成中,安息香缩合反应的历程一般被认为是由CN基和C=O基加成形成羟腈(后者含有活泼α-H,容易被除去生成C离子),接着和另一分子的醛加成,最后经质子转移,消除CN基而得安息香。其反应历程可参阅一般有机化学教材。但是,由于在反应中使用了剧毒的氰化物而显得十分麻烦。近年来,已有改用广泛存在的生物辅酶一维生素B_1~*(即盐酸硫胺)作催化剂合成安息香类的报导。本文报导了用此法研究苯甲醛的缩合工作,此法不仅材料易得、便宜,并且操作安全,效果良好,尤其是,经这一改进,使安息香缩合反应在实验室应用成为可能。
In organic synthesis, the process of benzoin condensation reaction is generally believed to be formed by the addition of CN and C = O groups to form cyanohydrins (the latter containing an active α-H which is easily removed to form C ions) followed by reaction with another molecule Aldehyde addition, and finally by proton transfer, elimination of CN-based and get benzoin. The reaction process can refer to the general organic chemistry textbook. However, it is cumbersome to use highly toxic cyanide in the reaction. In recent years, the use of widely used biological coenzyme B_1 ~ * (ie, thiamine hydrochloride) as a catalyst for the synthesis of benzoin reported. This paper reports the study of the condensation of benzaldehyde by this method. This method not only has the advantages of easy availability, low cost, safe operation and good effect, but also makes it possible to use benzoin condensation reaction in the laboratory.