Heterocycles by Ring Closure of Ortho-Substituted t-Anilines (The t-Amino Effect)

摘要: Publisher Summary It is the purpose of this chapter to collate all available material relating “t-amino effect” and attempt a rationalization its operative influence in mechanistic manner. The cyclizations ortho-substituted t-anilines are described two main sections. first discusses ring closures between ortho substituent t-nitrogen. Varieties seemingly unrelated reactions have been reported which t-aniline with an type N-C-Y converted into benzimidazole loss group from All these can be rationalized by intermediacy imine bearing good leaving group. While second deals those formations involve a-methylene groups attached nitrogen. fall category conform basic mechanism for unsaturated (A=B) capable mesomerism. polarized mesomer set up further reaction since hydrogens rendered labile charged nitrogen, consequently abstracted nucleophilic center (B-). Here, discussion will divided sections according functiona1 (o-nitroso o-nitro groups, o-amino o-acylamino o-azo group, o-azomethine (=n=c), o-carbonyl (c=o) o-imine (c=n) groups) situated at position.