Pyrazolinones nitration

As expected, nitration is facilitated by activating groups such as an amino group for example, nitration of (115) occurs at about 20 °C (HNO3/H2SO4). Sydnones (116) are nitrated readily. The pyrazolinone (117) is nitrated as indicated, and 1,2,4-triazolinones have also been ring nitrated. 

Electrophilic substitution occurs readily in Af-phenyl groups, e.g. 1-phenyI-pyrazoIes, -imidazoles and -pyrazolinones are all nitrated and halogenated at the para position. The aryl group is attacked preferentially when the reactions are carried out in strongly acidic media, where the azole ring is protonated. 

In addition to the nickel complexes (38) already described, copper complexes of the pyrazolinone ligands (36) and (37) are effective against the same fungi (see Section 66.7.I.92 Chloride or nitrate were the anions in the copper complexes. 

---