申请人:Arch Chemicals, Inc.
公开号:US20130211093A1
公开(公告)日:2013-08-15
Disclosed herein is a cost effective and environmentally friendly process to prepare 1-hydroxy-6-substituted pyridones from 2,6-dichloropyridine. The process includes the steps of (a) reacting 2,6-dichloropyridine with hydrogen peroxide in the presence of trifluoroacetic acid at a first temperature to produce a first intermediate containing (1) trifluoroacetic acid and (2) 2,6-dichloropyridine N-oxide and/or salts thereof; (b) adding sulfuric acid to the first intermediate to provide a second intermediate; (c) removing trifluoroacetic acid from the second intermediate to provide a composition containing 2,6-dichloropyridine N-oxide and/or salts thereof which is essentially free of trifluoroacetic acid; (d) reacting 2,6-dichloropyridine N-oxide and/or salts thereof from step (c) with RXH and a base wherein each R is independently a substituted or unsubstituted hydrocarbyl group having between 1 and 20 carbon atoms, X is oxygen or sulfur, to produce a corresponding 2,6-disubstituted-pyridine N-oxide; and (e) heating the disubstituted compound thereby producing the 1-hydroxy-6-substituted pyridone.
本文揭示了一种成本效益且环保的方法,用于从2,6-二氯吡啶制备1-羟基-6-取代吡啶酮。该方法包括以下步骤:(a)在第一温度下,在三氟乙酸存在下将2,6-二氯吡啶与过氧化氢反应,生成含有三氟乙酸和2,6-二氯吡啶N-氧化物和/或其盐的第一中间体;(b)向第一中间体中加入硫酸,得到第二中间体;(c)从第二中间体中去除三氟乙酸,得到一个基本上不含三氟乙酸的含有2,6-二氯吡啶N-氧化物和/或其盐的组合物;(d)将步骤(c)中的2,6-二氯吡啶N-氧化物和/或其盐与RXH和碱反应,其中每个R独立地是具有1至20个碳原子的取代或未取代的烃基,X是氧或硫,以生成相应的2,6-二取代吡啶N-氧化物;(e)加热二取代化合物,从而产生1-羟基-6-取代吡啶酮。