A new, efficient process for the synthesis of 5-acetyl-1H-pyrazole-3-carboxylic acid,
a versatile building block and the key intermediate of darolutamide, using diethyl
pyrazole-3,5-dicarboxylate as the starting material is described. Contrary to the
synthetic routes known from the literature, this procedure does not apply explosive
diazo reagents, moreover it is simple and safe, thereby suitable for scale-up.
