Metal nitrate promoted highly regiospecific ortho–nitration of phenols: Application to the synthesis of nitroxynil

Highly regiospecific ortho–nitration of electronically diverse phenols is accomplished using Fe(NO3)3.9H2O for electron–rich and Cu(NO3)2.6H2O for electron–deficient phenols as the cheap nitrating agents. The reaction is carried out in CH3CN at 90 °C under mild and neutral conditions where structurally diverse phenols afford exclusively ortho–nitration products in moderate to good yields with outstanding tolerance of functional groups. The synthetic application of this strategy was established by achieving the bioactive compound nitroxynil.