New Reactions of N‐tert‐Butylimines; Formation of N‐Heterocycles by Methyl Radical Elimination on Flash Vacuum Thermolysis of N‐Benzylidene‐ and N‐(2‐Pyridylmethylidene)‐tert‐butylamines

Abstract

Thermal reactions of N-benzylidene- and N-(2-pyridylmethylidene)-tert-butylamines (5 and 13) under FVT conditions have been investigated. Unexpectedly, at 800 °C, compound 5 yields 1,2-dimethylindole and 3-methylisoquinoline. In the reaction of 13 at 800 °C, 3-methylimidazo[1,5-a]pyridine was obtained as the major product. Mechanisms of these reactions have been proposed on the basis of DFT calculations. Furthermore, UV-photoelectron spectroscopy combined with FVT has been applied for direct monitoring and characterization of the thermolysis products in situ.

Flash Vacuum Thermolysis of N‐(3‐ and 4‐Pyridylmethylidene)‐tert‐butylamines: Mechanisms of Formation of Pyrrolopyridines and Naphthyridines

“…To explain these results we have proposed a free radical mechanism, involving initial loss of a methyl group from the tert ‐butyl groups to generate a resonance stabilized 2‐azaallyl radical 2 . Cyclization of this to an aziridinyl radical 3 or a 1,4‐H shift to generate 1‐azaallyl radical 5 followed by cyclization accounted for the observed products 2b…”

“…Furthermore, aromatic tert ‐butylimines behave very unexpectedly under these conditions. Thus, FVT of N ‐benzylidene‐ tert ‐butylamine 1a at 800 °C results in the formation of 1,2‐dimethylindole 4 and 3‐methylisoquinoline 6 , whereas N ‐(2‐pyridylmethylidene)‐ tert ‐butylamine 1b gives rise to 3‐methylimidazo[1,5‐ a ]pyridine 7 in high yield (Scheme ) 2b…”

The Electronic Structure of Some Cyanohydrins—A Spectroscopically Under‐Investigated Family of Compounds

“…All the spectra were recorded using the previously described spectrometer. [27] AH e-I radiation source (21.21 eV and/or 48 eV) and a1 278 cylindrical constant energy analyzer were used, with 5x10 À6 hPa working pressure and 10 À7 hPa channeltron (X914L) pressure. The spectra resulting from as ingle scan were built from 2048 points and are accurate within 0.03 eV.S pectra were calibrat-ed against the lines of xenon (12.13 and 13.44 eV) and argon (15.76 and 15.94 eV).…”

“…All the calculations were performed using the Gaussian 09 [28] program package, Revision D.01, with the 6-311G(d,p) basis set and the previously detailed approach. [27] DFT [29][30][31][32][33] /CAM-B3LYP [34][35][36][37] was used for all geometry optimizations and was followed by frequency calculations to verify that the stationary points obtained were www.chemphyschem.org true energy minima. IEs were calculated on the most stable conformer (see the SI) with DSCF/TD-DFT (IE = E cation ÀE neutral ).…”

Preise des Royal Australian Chemical Institute: A. O'Mullane, B. J. Smith, M. G. Banwell, R. J. Payne, D. M. D'Alessandro und C. Wentrup / Preise der Schweizerischen Chemischen Gesellschaft: G. Gasser und N. Banerji

“…experimentell und theoretisch mithilfe der Photochemie, der Blitzvakuumthermolyse und mikrowelleninduzierter chemischer Reaktionen. In Chemistry—A European Journal hat er neue Reaktionen von N ‐ tert ‐Butyliminen vorgestellt6a und im European Journal of Organic Chemistry die Bildung von Pyrrolopyridinen und Naphthyridinen mithilfe der Blitzvakuumthermolyse 6b. Wentrup war Gründungsmitglied im Editorial Board von Chemistry—A European Journal .…”