1 3- Dimethyl-5- Pyrazolone

1,3-dimethyl-5- pyrazolone is a yellow, crystalline solid with a melting point of 108-110 degree centigrade and a molecular weight of 126.16 g/mol. This organic compound with the chemical formula C₅H₈N₂O is synthesized through the reaction of ethyl acetoacetate with hydrazine hydrate followed by cyclization. Ethyl acetoacetate is first reacted with hydrazine hydrate in the presence of a catalyst to form 1,2-dihydro-3H-pyrazol-3-one. The resultant is then cyclized using a dehydrating agent to form 1,3-dimethyl-5-pyrazolone. This water soluble white or off-white crystalline powder is widely used as an intermediate in the synthesis of pharmaceuticals, agrochemicals, dyes, and other organic compounds. It can also be used as a chelating agent and in the production of rubber and plastics.