Synthesis of 3-substituted 1-phenyl-1H-pyrazole-4-carbaldehydes and the corresponding ethanones by Pd-catalysed cross-coupling reactions

An efficient synthetic route to construct ortho-substituted 1-phenyl-1H-pyrazole-4carboxaldehydes and the corresponding ethanones starting from 1-phenyl-1H-pyrazol-3-ol is described.Carbon-carbon bond-forming Pd-catalysed cross-coupling reactions were applied for the functionalisation of the intermediate pyrazole triflates.Detailed NMR spectroscopic investigations were undertaken with all obtained products.