申请人:Eastman Kodak Company
公开号:US04366321A1
公开(公告)日:1982-12-28
Disclosed are novel intermediates and their preparation, and the preparation therefrom of 2-halo-3-nitro-5-acyl thiophenes which themselves are important intermediates for the preparation of azo dyes of the type, ##STR1## wherein C.sup.1 represents typically any aniline, tetrahydroquinoline, benzomorpholine or the like coupler and the acyl group contains from 1-10 carbons. It has been found that if 2-acyl thiophene is treated with a hydroxylamine compound, e.g., a salt of hydroxylamine, including sulphate, chloride or the like, to form the oxime prior to the 2-position halogenation and 3-position nitration steps, various side reactions such as halogenation of the acyl group and nitration of the 5-position are avoided, the yield of each step is improved, and the reactions are less sensitive to the deleterious effects of temperature variations and excess reactants. The oxime derivative is readily reconverted to the acyl derivative after the halogenation and nitration steps have been completed. This product is then readily aminated to give the 2-amino derivative.
揭示了新型中间体及其制备方法,以及从中制备2-卤代-3-硝基-5-酰基噻吩的方法。这些化合物本身是制备偶氮染料的重要中间体,偶氮染料的结构如下:其中C.sup.1通常表示任意苯胺、四氢喹啉、苯吗啉或类似的偶联剂,酰基含有1-10个碳原子。发现如果先将2-酰基噻吩与羟胺化合物(例如,羟胺的盐,包括硫酸盐、氯化物等)反应形成肟,然后再进行2-位置卤代和3-位置硝化的步骤,可以避免各种副反应,如酰基的卤代和5-位置的硝化,提高每个步骤的产率,并且反应对温度变化和过量反应物的不良影响不太敏感。在卤代和硝化步骤完成后,肟衍生物可以轻松地重新转化为酰基衍生物。然后,该产物可以轻松地进行胺化反应,得到2-氨基衍生物。