Cyclicalkoxyguanidines such as 2-methoxyiminoimidazolidine, 2-benzyloxyiminoimidazolidine and 6',7'-dihydro-5' H-spiro(cyclohexane-1,3'-imidazo(2,1-c)(1,2,4)oxadiazole react with isocyanates and isothiocyanates to give the corresponding urea and thiourea derivatives, which under basic reaction conditions undergo an intramolecular SN2σ nucleophilic substitution reaction at the sp 2 nitrogen atom of
Synthesis of Heterocycles by Intramolecular Nucleophilic Substitution at an Electron-Deficient sp2 Nitrogen Atom
作者:Jarosław Sączewski、Maria Gdaniec
DOI:10.1002/ejoc.200901520
日期:2010.4
1-c][1,2,4]thiadiazoles have been synthesized by intramolecularnucleophilicsubstitution reactions at the electron-deficient sp(2) nitrogen atom of 2-(hydroxyimino)imidazolidine O-sulfonate. The displacement of the sulfate leaving group by both nitrogen and sulfur anionic nucleophiles proceeds exothermically by in-plane S(N)2 sigma nucleophilicsubstitution.