1, 4-and 1, 7-Addition Reactions of 4-(Substituted benzylidene)-3, 5-dimethylisopyrazoles

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.