RESUMO
An intramolecular 1,3-dipolar cycloaddition strategy for rapid entry into triazole-fused heterocyclic compounds without recourse to the traditional Cu(1)-catalyzed azide-alkyne cycloadditions is described. Central to the strategy is the in situ generation of substituted diazomethanes in a two-step sequence from the corresponding aldehydes, which then undergo smooth cycloaddition with a cyano group to generate the desired fused 1,2,3-triazoles in good overall yields. The entire sequence can be carried out in a one-pot operation.
Assuntos
Diazometano/química , Compostos Heterocíclicos/síntese química , Nitrilas/química , Triazóis/síntese química , Aldeídos/química , Alcinos/química , Catálise , Cobre/química , Reação de Cicloadição , Compostos Heterocíclicos/química , Estrutura Molecular , Triazóis/químicaRESUMO
In our pursuit of an efficient, protecting-group-free synthesis of the dual CCK1/CCK2 receptor antagonist 1, we have developed chemoselective conditions for sulfonamide formation reaction in pure water and a PhNMe(2) mediated carboxamide formation, both in the presence of a carboxylic acid. Practical synthesis of an unnatural, chiral ß-aryl-α-amino acid is also described.
Assuntos
Receptor de Colecistocinina A/antagonistas & inibidores , Receptor de Colecistocinina B/antagonistas & inibidores , Estrutura Molecular , EstereoisomerismoRESUMO
A concise synthesis of fused benzo[4,5]furo heterocycles 18 has been developed. Chemo/regioselective Suzuki coupling between 1,2-dihaloarene 17 and alpha-hydroxyphenylboronic acid or ester 20 gives biaryl phenol 19, which then undergoes copper(I) thiophene-2-carboxylate (CuTC)-mediated intramolecular cyclization to afford 18 in good overall yield. This method has broad substrate scope and allows facile assembly of a wide variety of benzo[4,5]furo heterocycles.
