Replacing Nitrous Acid

  • Author: ChemViews Magazine
  • Published Date: 12 December 2017
  • Source / Publisher: European Journal of Inorganic Chemistry/Wiley-VCH
  • Copyright: Wiley-VCH Verlag GmbH & Co. KGaA
thumbnail image: Replacing Nitrous Acid

Related Societies

Nitrous acid (HNO2) can be used in nitrosation and nitration reactions. However, the strongly acidic and oxidizing character of nitrous acid means harsh reaction conditions, which can limit the substrate scope and cause the formation of by-products. Dinitrogen trioxide, N2O3, dissociates into nitric oxide (NO) and nitrogen dioxide (NO2) radicals (pictured) and could theoretically be used to replace nitrous acid as a reactant. Unfortunately, N2O3 is quite unstable.

Kristopher A. Rosadiuk and D. Scott Bohle, McGill University, Montreal, Canada, have used organic solvents to stabilize N2O3 and enable its use in nitrosation and nitration reactions.The team prepared N2O3 solutions by alternately passing NO gas and oxygen through a dry solvent cooled to 0 °C. The formed reagent can then directly be used in a one-pot reaction approach to prepare, e.g., benzenediazonium nitrite ([PhN2][NO2]), nitrosyl chloride (NOCl), or nitrosylsulfuric acid, (ONOSO3H).

Most aprotic solvents that are either polar or aromatic can stabilize N2O3. The team used solutions in, e.g., acetic anhydride, acetone, acetonitrile, benzene, chlorobenzene, chloroform, dichloromethane, dimethyl sulfoxide (DMSO), ethyl acetate, tetrahydrofuran (THF), and toluene. According to the researchers, N2O3 could become a useful reagent in synthesis using this solvent-stabilization approach.


Article Views: 3856

Sign in Area

Please sign in below

Additional Sign In options

Please note that to comment on an article you must be registered and logged in.
Registration is for free, you may already be registered to receive, e.g., the newsletter. When you register on this website, please ensure you view our terms and conditions. All comments are subject to moderation.

Article Comments - To add a comment please sign in

If you would like to reuse any content, in print or online, from, please contact us first for permission and consult our permission guidance prior to making your request

Follow on Facebook Follow on Twitter Follow on YouTube Follow on LinkedIn Follow on Instagram RSS Sign up for newsletters

Magazine of Chemistry Europe (16 European Chemical Societies) published by Wiley-VCH