Flash vacuum thermolysis of N-(3-and 4-Pyridylmethylidene)-tert- butylamines: Mechanisms of formation of pyrrolopyridines and naphthyridines

K. Justyna , S. Leśniak , R.B. Nazarski , M. Rachwalski , T.Y. Vu , T.K.X. Huynh , S. Khayar , Alain Dargelos (1) , Anna Chrostowska (1) , C. Wentrup

1 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux

Pyrrolopyridines and naphthyridines are formed by flash vacuum thermolysis (FVT) of 3-and 4-pyridylmethylidene-tert-butylimines 8 and 15. Elimination of a methyl radical generates resonance stablized 2-azaallyl radicals a1 and b1. The formation of pyrrolopyridines 9, 16 and 17 is rationalized in terms of cyclization of 1-aziridinyl radicals a2 and b2. Formation of naphthyridine 10 from imine 8, and of 11 and 18 from imine 15, are in accord with cyclization of 1-azaallyl radicals a6 and b9. Formation of naphthyridine 11 from 8, and of 10 and 19 from 15, indicate the operation of the spiro-cyclization pathways forming intermediates a9 and b14. Formation of the 1,8-naphthyridine 20 (3%) indicates a rearrangement through aziridine b22 and biradical b23. DFT calculations at the CAM-B3LYP/6-311G(d,p) level support the proposed reaction mechanisms. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mots clés: density functional calculations; heterocycles; High-temperature reactions; Photoelectron Spectroscopy; radicals; Rearrangement

Domaines: Chimie inorganique; Chimie organique

K. Justyna, S. Leśniak, R.B. Nazarski, M. Rachwalski, T.Y. Vu, et al.. Flash vacuum thermolysis of N-(3-and 4-Pyridylmethylidene)-tert- butylamines: Mechanisms of formation of pyrrolopyridines and naphthyridines. European Journal of Organic Chemistry, 2014, 2014 (14), pp.3020--3027. ⟨10.1002/ejoc.201400112⟩. ⟨hal-01566321⟩