Antioxidant activity of 3-methyl-1-phenyl-2-pyrazolin-5-one.

  title={Antioxidant activity of 3-methyl-1-phenyl-2-pyrazolin-5-one.},
  author={Yuji Yamamoto and Tomohiro Kuwahara and Kazunori Watanabe},
  journal={Redox report : communications in free radical research},
  volume={2 5},
The antioxidant activity of an anti-ischemic agent, 3-methyl-1-phenyl-2-pyrazolin-5-one (MCI-186), was examined. The pKa value of MCI-186 is 7.0 and the rate of oxidation of MCI-186 initiated with an azo compound increased with increasing pH, suggesting that the anionic form of MCI-186 is much more reactive than the non-ionic form. The major products were 3-methyl-1-phenyl-2-pyrazolin-4,5-dione (4,5-dione) and 2-oxo-3-(phenylhydrazono)-butanoic acid (OPB). Hydrolysis of 4,5-dione gave OPB. The… CONTINUE READING