3.5- Dimethyl-4-chloropyrazol

Tautomerism of 3,5-bis(4-methylpyrazol-l-yl)-4-methylpyrazole (202) also involves the simultaneous rotation of the two lateral rings and has a value of 12 kcal mol-1 (in methanol), almost the same as 3,5-dimethyl-4-chloropyrazole and 3,5-dimethyl-4-nitropyrazole (93CJC1443). 

Potassium hydroselenide is allowed to act upon the methiodide of l-phenyl-3 4-dimethyl-5-chloropyrazole, when long, thin, yellow... 

Formation of C-sulfonyl derivatives of pyrazoles and indazoles <84CHEC-I(5)167> has been updated <90AHC(47)139>. A significative example is the synthesis of the 4-sulfonyl chloride derivative by reacting l,3-dimethyl-5-chloropyrazole with chlorosulfonic acid <86JCR(S)388>, subsequent treatment with ammonia affords the sulfonamide. 

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