124460-03-3Relevant academic research and scientific papers
2-AZIDO- AND 3-AZIDO-1-METHYLINDOLE: SYNTHESIS, THERMAL REACTIVITY, 1H- AND 13C NMR SPECTRAL PROPERTIES, AND SEMIEMPIRICAL MNDO-PM3 STRUCTURAL CALCULATIONS
Foresti, Elisabetta,Gioia, Maria Teresa Di,Nanni, Daniele,Zanirato, Paolo
, p. 151 - 162 (2007/10/02)
2-Azido-, 1, and 3-azido-1-methylindole, 2 are prepared by azido group transfer reaction of the appropriate heteroaryllithium derivative with p-toluenesulphonyl azide.Mild thermal fragmentation of azide 1 in inert solvent leads to a ring-opened ortho-quinone cyanomethide methylimine intermediate A which, by cyclodimerization followed by rearrangement, mainly affords N,N'-dimethyl-N-(cis-α,β-dicyanostyr-2-yl)-1,2-phenylenediamine whose molecular structure was confirmed by an X-ray crystal structure determination.In addition, azide 1 generally reacts with terminal or 1,2-disubstituted E or Z alkenes to give aziridines (arising by extrusion of nitrogen and ring-contraction of former triazolines) as well as 4-cyanotetrahydroquinolines, the Diels-Adler cycloadducts of A; however, in the presence of 1-pyrrolidino-1-cyclopentene it only affords the appropriate triazoline in quantitative yields.On the other hand, azide 2 fails to react similarly with alkenes, but in the presence of alkynes, viz. (trimethylsilyl)acetylene and methyl propiolate, affords the corresponding triazoles five times faster than the isomeric azide 1.Kinetic measurements indicated that azides 1 and 2 exhibit first-order thermal decomposition with comparable activation parameters (Ea = 23.0 and 22.1 kcal mol-1, ΔS% = -8.1 and -9.8 cal mol-1 K-1, respectively).Ground-state electron density distributions and geometries are presented for both azides 1 and 2 as determined by semiempirical MNDO-PM3 calculations.
