The demand for azobenzenes has exponentially grown due to their wide range of applications in textile, medical, and dye industries. Here we report a procedure to synthesise azobenzenes by the dehydrogenative coupling of anilines in the presence of Co-II(TPP) (TPP=dianion of tetraphenyl porphyrin) catalyst and 4-nitrophenyl azide oxidant species. Differently substituted azobenzenes were obtained in yields up to 72 % together with 4-nitrophenyl amine, which is the stoichiometric by-product of the process. The procedure displayed a good sustainability due to the almost quantitative recovery of pure 4-nitrophenyl amine that can be transformed again into the desired azide to pave the way for an efficient circular process. Experimental data supported the occurrence of a radical mechanism mediated by putative nitrene radical cobalt intermediate.

Cobalt Porphyrin-Catalysed Synthesis of Azobenzenes by Dehydrogenative Coupling of Anilines / C. Damiano, M. Cavalleri, N. Panza, E. Gallo. - In: EUROPEAN JOURNAL OF ORGANIC CHEMISTRY. - ISSN 1099-0690. - 2022:34(2022 Sep 13), pp. e202200791.1-e202200791.7. [10.1002/ejoc.202200791]

Cobalt Porphyrin-Catalysed Synthesis of Azobenzenes by Dehydrogenative Coupling of Anilines

C. Damiano
Primo
;
M. Cavalleri
Secondo
;
N. Panza
Penultimo
;
E. Gallo
Ultimo
2022

Abstract

The demand for azobenzenes has exponentially grown due to their wide range of applications in textile, medical, and dye industries. Here we report a procedure to synthesise azobenzenes by the dehydrogenative coupling of anilines in the presence of Co-II(TPP) (TPP=dianion of tetraphenyl porphyrin) catalyst and 4-nitrophenyl azide oxidant species. Differently substituted azobenzenes were obtained in yields up to 72 % together with 4-nitrophenyl amine, which is the stoichiometric by-product of the process. The procedure displayed a good sustainability due to the almost quantitative recovery of pure 4-nitrophenyl amine that can be transformed again into the desired azide to pave the way for an efficient circular process. Experimental data supported the occurrence of a radical mechanism mediated by putative nitrene radical cobalt intermediate.
Azobenzene; Amines; Azides; Co(TPP); Dehydrogenative coupling;
Settore CHIM/03 - Chimica Generale e Inorganica
15-ago-2022
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/944474
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