Pyrazole-3,4-dicarboxylic acid

Pyrazole-3,4-dicarboxylic acid, 1-phenyl-dimethyl ester synthesis, 5, 150 Pyrazole-3,5-dione, 1-phenyl-alkylation, 5, 230 synthesis, 5, 290... 

Diazopropyne reacts similarly with a monosubstituted acetylene to form 3(5)-alkynylpyrazoles (68LA113). Thus, the reaction of diazopropyne with acetylene-carboxylic acid methyl ether results in 5-ethynyl-l//-pyrazole-3-carboxylic acid methyl ether in 48 h in 62% yield. 5-Ethynyl-l//-pyrazole-3,4-dicarboxylic acid dimethyl ester was prepared by reaction of diazopropyne with acetylenedicar-boxylic acid methyl ether (Scheme 10). 

Chloride, in B-00287 Chromopyrazole I, C-00287 4,5-Dihydro-1 V/-pyrazole-3,4-dicarboxylic acid Diamide, A-di-Me, in D-00480 Gallein, G-00004... 

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