Synthesis and Crystal Structure of 5-Chloro-3-Methyl-1-Phenyl-1H-Pyrazole-4-Carbaldehyde

The title compound, 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde 2 , was prepared in a series of syntheses to produce new pyrazole derivatives, and its crystal structure was determined by X-ray diffraction method. The crystal belongs to monoclinic, space group P 2 1 / c with unit cell parameters a = 6.7637(4) Å, b = 6.8712(3) Å, c = 22.4188(10) Å, β = 93.8458(14)º, V = 1039.56(9) Å 3 and Z = 4. X-Ray reveals that the aldehydic fragment is almost coplanar with the adjacent pyrazole ring, but the two ring planes are inclined at 72.8(1)º. The molecule is linked to its neighbor by two directionally specific C–H···O interactions. Index Abstract A highly versatile intermediate, 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde, was synthesized and its structure determined.