4-Ethynyl-5-chloro-1,3-dimethylpyrazole

Cross-coupling of 5-ethynyl-4-chloro-l,3-dimethylpyrazole with 3-iodo-4-chloronitrobenzene was carried out in the presence of (PPh3)2PdCl2, Cul, and EtjN (66%) (96MC98) (Scheme 69). 

From 4-chloroethynyl-l,3-dimethylpyrazole 80% of 4-ethynyl-5-chloro-l,3-dimethylpyrazole was obtained. There is simultaneous formation of about 10% of 4-ethynyl-l,3-dimethylpyrazole (76IZV2148 77IZV2306) (Scheme 106). 

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