1,4- and 1,7-Addition reactions of 4-(substituted benzylidene)-3,5-dimethylisopyrazoles.
作者:TAKUSHI KURIHARA、YASUHIKO SAKAMOTO、TOSHIKO SAKAGUCHI、HIROSHI HIRANO
DOI:10.1248/cpb.26.1141
日期:——
Reactions of 4-(substituted benzylidene)-3, 5-dimethylisopyrazoles (1a-1c) with acetic anhydride, hydrochloric acid in methanol, bromine in acetic acid, dimethyl sulfate, and acyl chlorides (acetyl chloride, benzoyl chloride, ethyl chloroformate, and p-toluenesulfonyl chloride) in pyridine gave 1, 4-addition products (2-10) in fairly good yield. On the other hand, 4-(o-nitrobenzylidene) isopyrazole (1a) was converted to 5-chloro-3-(1-substituted 3, 5-dimethylpyrazolyl) anthranils (13, 14, and 15) by treatment with acetyl chloride, benzoyl chloride, or ethyl chloroformate without pyridine.
4-(取代苄基)-3, 5-二甲基异吡唑(1a-1c)与酸酐、盐酸甲醇溶液、醋酸中的溴、二甲基硫酸盐以及吡啶中的酰氯(如醋酰氯、苯甲酰氯、乙基氯甲酸酯及对甲苯磺酰氯)的反应产生了相对较好的1, 4-加成产物(2-10)。另一方面,4-(邻硝基苄基)异吡唑(1a)与醋酰氯、苯甲酰氯或乙基氯甲酸酯反应后,未使用吡啶,生成了5-氯-3-(1-取代的3, 5-二甲基吡唑基)氨基苯甲酸(13, 14, 和15)。