Phenols do not have an H atom attached to the C atom carrying the OH group. Therefore, their reaction with oxidizing agents is quite different from that of primary or secondary alcohols. Only very strong oxidizing reagents, such as permanganate, dichromate or Fremy's salt (KSO3)2NO, oxidize simple phenols to 2,5-cyclohexadien-1,4-ones (benzoquinones). The following equation represents the oxidation of ortho-methylated phenol.