The nitro group can be displaced by nucleophiles. Thus, tert-butanethiol gives 2-tert-butylthiobenzaldehyde, a useful intermediate for thiocoumarins and other sulfur-containing heterocycles: Synthesis, 56 (1978). For reduction with FeSO4 to the unstable 2-aminobenzaldehyde, see: Org. Synth. Coll., 3, 56 (1955).
