Synthesis of nitro compounds
The high reactivity of ozone and its propensity to overoxidize organic molecules, including most solvents can largely be mitigated by adsorbing both substrate and ozone onto silica gel, providing a solvent-free oxidation method. A flow-based packed bed reactor approach provides exceptional control of temperature and time for oxidation of amines to nitroalkanes and the synthesis of pyridine N-oxides.
E. A. Skrotzki, J. K. Vandavasi, S. G. Newman, J. Org. Chem., 2021, 86, 14169-14176.
Several primary aromatic amines were converted to their corresponding nitro compounds in good yields with sodium perborate tetrahydrate (SPB) in micellar media in the presence of a catalytic amount of tungstophosphoric acid (H3PW·nH2O).
H. Firouzabadi, N. Iranpoor, K. Amani, Green Chemistry, 2001, 3, 131-132.
The use of nonanebis(peroxoic acid) enables a regio- and chemoselective oxidation of aromatic amines hindered with an ortho substituent to the corresponding nitro compounds, except for anilines ortho-substituted with amino groups (NH2, NHR) or hydroxyl groups, where H-bonding between an hydrogen of the adjacent group and an oxygen atom from the diperoxy acid directs the oxidation.
V. V. Patil, G. S. Shankarling, J. Org. Chem., 2015, 80, 7876-7883.