A flexible Pinner preparation of orthoesters: the model case of trimethylorthobenzoate
作者:Marco Noè、Alvise Perosa、Maurizio Selva
DOI:10.1039/c3gc40774h
日期:——
In the absence of additional solvents, a novel procedure was implemented for the synthesis of trimethylorthoesters through the Pinner reaction. At 5 °C, the reaction of both aliphatic and aromatic nitriles (RCN; R = Et, Bu, Ph) with a moderate excess of MeOH and gaseous HCl gave the corresponding imidate hydrochlorides [RC(NH)OR′·HCl] in excellent yields (>90%). At 25–65 °C, the methanolysis of alkyl
在没有额外的情况下 溶剂,通过Pinner反应,实现了用于合成三甲基原酸酯的新方法。在5°C下,脂族和芳族的反应腈 (RCN; R = Et,Bu,Ph),其中有适度的过量 甲醇气态HCl收率很高(> 90%),得到相应的亚氨酸盐酸盐[RC(NH)OR'·HCl]。在25–65°C时,亚氨酸烷基酯盐的甲醇分解提供了原丙酸三甲酯和戊酸,而仅观察到了痕量原苯甲酸三甲酯(TMOB)。但是,芳香盐酸盐可以很容易地转化为磷酸氢盐[PhC(NH)OR'·H 3 PO 4 ],然后与之进行选择性(> 80%)反应甲醇以62%的分离产率生产TMOB。从此开始,TMOB的空前Pinner型合成成为可能苄腈而不是剧毒 三氯甲基苯。总体而言,在安全性和过程强化方面取得了显着改善。