Hydrogenation of Nitro-Substituted Acetophenones

Jackson, S. D. , McEwan, R. and Spence, R. R. (2009) Hydrogenation of Nitro-Substituted Acetophenones. In: Prunier, M. L. (ed.) Catalysis of Organic Reactions. CRC Press: Boca Raton, pp. 79-86. ISBN 978-1-4200-7076-7

Abstract

We have examined the hydrogenation of ortho-, meta- and para-nitroacetophenone to the respective aminoacetophenone in the liquid phase over a Pd/Carbon catalyst. The meta- and para-substituted nitroacetophenones gave high selectivity to the aminoacetophenones; however, the ortho-nitroacetophenone, which was the least reactive of the three isomers, produced 1-indolinone as well as ortho-aminoacetophenone. The selectivity to 1-indolinone was typically similar to 10%. The formation of this product revealed an internal cyclisation reaction. Formation of such a cyclic product Would indicate nitrene insertion into a C-H bond, hence suggesting Ar-N as a surface intermediate in the hydrogenation of the nitro-group. This species is rarely considered in mechanistic interpretations of nitro-group hydrogenation over metal surfaces. However, in this system we have, in effect, a chemical trap that allows us to identify the intermediate giving a far clearer insight into the reaction mechanism.

• Item Type: Book Sections
• Additional Information: Twenty-second Conference
• Keywords: bond, catalysis, hydrogenation, kinetics, liquid phase hydrogenation, mechanism, nickel, nitrobenzene hydrogenation, nitrocompounds, nitrosobenzene, palladium catalysts, phase, platinum catalyst, reduction, selectivity, surface
• Status: Published
• Glasgow Author(s) Enlighten ID: Jackson, Professor David and Spence, Mr Ronald
• Authors: Jackson, S. D., McEwan, R., and Spence, R. R.
• College/School: College of Science and Engineering > School of Chemistry
• Publisher: CRC Press
• ISBN: 978-1-4200-7076-7