The invention relates to a new general method for the reduction of nitroarenes to anilines using a Mo(VI) catalyst and pinacol as reducing agent. The products obtained show excellent yields. It should be noted that this new method uses an easily available and non-toxic reducing agent that generates non-toxic byproducts which are easily separated from the amine synthesized.
New and innovative aspects
The main novelty of the present invention is the use of pinacol as reducing agent that entails undeniable advantages over clasical methods for the reduction of nitro compounds, which are encompassed in the two following groups: (a) catalytic hydrogenation using molecular hydrogen, and (b) chemical reduction, usually with a metal in acidic media.
Main advantages of its use
The advantages of the new method over the clasical ones are:
-Over catalytic hydrogenation: the reaction is more selective, avoinding side-reduction of other groups such as olefins, carbonyls, nitriles or halogens. The new method does not implie the use and storage of hydrogen gas, all the reactives are solids or liquids easy to handle.
- Over the reduction with metals in acidic media: The new method is more selective, allows the reduction of compounds with acid-sensitive fuctional groups and uses catalytic amounts of the metal complex (not always posible in the reductions in acidic media).
-Over both clasical methods: the new process generally involves shorter reaction times and milder conditions. The reaction is set up in open air, there is no need of inert atmosphere. Main byproducts are water and acetone, environmentally friendly and easy to remove from the reaction media. The amines are isolated in pure analytical form whithout column chromathography (economic and environmental advantages).
The present invention relates to a procedure for the catalytic reduction of organic compounds that contain a nitro functional group to compounds that contain an amino functional group by using pinacol (2,3-dimethyl-2,3-butanediol) as reducing agent in the presence of a Mo (VI) catalyst at atmospheric or higher pressure and a temperature between 110-150 ºC, generating as main byproducts water and acetone.
Synthesis of aromatic amines, that can show diverse already demonstrated properties (drugs, pesticides, materials,…). Therefore, applications in pharmaceutical and agrochemical industries.
Intellectual property status
Protected by Patent P201100596. Patent granting date: 05/07/2013
Current development status
Research or Experimental
Desired business relationship