A clean process has been developed for the synthesis of 2-adamantylphenol derivatives through adamantylation of substituted phenols with adamantanols catalyzed by commercially available and recyclable ion-exchange sulfonic acid resin in acetic acid. The sole byproduct of the adamantylation reaction, namely water, could be converted into the solvent acetic acid by addition of a slight excess of acetic anhydride during the work-up procedure, making the process waste-free except for regeneration of the ion-exchange resin, and facilitating the recycling of the resin catalyst. The ion-exchange sulfonic acid resin catalyst could be readily recycled by filtration and directly reused at least ten times without a significant loss of activity. The key intermediate of adapalene, 2-(1-adamantyl)-4-bromophenol, could be produced by means of this waste-free process.
已经开发出一种清洁的过程,通过商业可获得且可循环利用的离子交换磺酸树脂在醋酸中催化取代酚类化合物与孔雀石醇进行孔雀石化反应合成2-孔雀石基苯酚衍生物。孔雀石化反应的唯一副产物,即水,可以通过在工作过程中添加少量过量的乙酸酐将其转化为溶剂乙酸,使得该过程除了再生离子交换树脂外无废物产生,并有助于催化剂树脂的循环利用。离子交换磺酸树脂催化剂可以通过过滤轻松回收,并在至少十次的直接再利用中没有明显的活性损失。通过这种无废物过程可以制备阿达帕林的关键中间体2-(1-孔雀石基)-4-溴苯酚。