RESUMO
[Chemical reaction: see text] Various substituted 2-aminotetrahydroazolopyridines and 2-aminohexahydroazolopyridines have been prepared by bromine-mediated addition of protected guanidine or urea to hydropyridine derivatives. The pH-dependent regioselective cleavage of the resulting aminal function led to the 2-aminoazole products III. The yields of the bicycles of type II, and their conversion into azoles III depends on the electronic properties of the substituents on the nitrogen of the tetrahydopyridine.
Assuntos
Aminas/química , Azóis/química , Piridinas/química , Cinética , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Estrutura Molecular , OxirreduçãoRESUMO
[reaction: see text] A simple synthesis of the fused tetrahydro-imidazopyridine 13 was accomplished via selective addition of protected guanidine to N-carbomethoxy-1,2-dihydropyridine in the presence of bromine. Base-mediated semicleavage of the aminal gave 4-substituted 2-aminoimidazole 14. With this new method, natural marine metabolite 3-amino-1-(2-aminoimidazol-4-yl)-prop-1-ene (1) and derivatives may now be prepared from pyridine. Ab initio calculations of the energies of tautomers I-IV and deuteration experiments have provided insight into their reactivity.