Electrophilic Cyclization of 2-Chalcogen-N-Alkynylimidazoles: Versatile Access to Imidazo[2,1-b]Chalcogenazoles

Electrophilic Cyclization of 2-Chalcogen-N-Alkynylimidazoles: Versatile Access to Imidazo[2,1-b]Chalcogenazoles

Roehrs, Juliano A.; Godoi, Benhur; Grimaldi, Tamiris B.; Sperança, Adriane; Zeni, Gilson

Abstract:

The synthesis of imidazole derivatives and their properties have been thoroughly reported in the literature. The synthetic methods to obtain multiple substituted imidazoles can be basically divided into two classes. The first approach is based on a construction of the imidazol nucleus after the substituents have been installed and properly functionalized. The second approach is based on a preformed imidazol to which carbon substituents are attached in successive order. In this context, electrophilic cyclizations of suitable unsaturated systems have been frequently utilized to construct a wide range of carbocycles and heterocycles. In this study, we optimized the preparation of imidazo[2,1- b]chalcogenazoles 2a via eletrophilic cyclization of 2-chalcogene-N-alkynylimidazoles 1a (Figure 1).

The synthesis of imidazole derivatives and their properties have been thoroughly reported in the literature. The synthetic methods to obtain multiple substituted imidazoles can be basically divided into two classes. The first approach is based on a construction of the imidazol nucleus after the substituents have been installed and properly functionalized. The second approach is based on a preformed imidazol to which carbon substituents are attached in successive order. In this context, electrophilic cyclizations of suitable unsaturated systems have been frequently utilized to construct a wide range of carbocycles and heterocycles. In this study, we optimized the preparation of imidazo[2,1- b]chalcogenazoles 2a via eletrophilic cyclization of 2-chalcogene-N-alkynylimidazoles 1a (Figure 1).

Palavras-chave:

DOI: 10.5151/chempro-14bmos-R0345-2

Referências bibliográficas

• [1] 1 (a) Grimmett, M. R. Imidazole and Benzimidazole Synthesis; Academic Press: New York, 1997; pp 1-143. (b) Bellina, F.; Cauteruccio, S.; Rossi, R. Tetrahedron 2007, 63, 4571.
• [2] 2 Bellina, F.; Rossi, R. Adv. Synth. Catal. 2010, 352, 1223.
• [3] 3 Godoi, B.; Schumacher, R. F.; Zeni, G. Chem. Rev. 2011, 111, 2937.
• [4] 4 Laroche, C.; Li, J.; Freyer, M. W.; Kerwin, S. M. J. Org. Chem. 2008,73, 6462.
• [5] 5 Laroche, C.; Kerwin, S. M. Tetrahedron Lett. 2009, 50, 5194.

Como citar:

Roehrs, Juliano A.; Godoi, Benhur; Grimaldi, Tamiris B.; Sperança, Adriane; Zeni, Gilson; "Electrophilic Cyclization of 2-Chalcogen-N-Alkynylimidazoles: Versatile Access to Imidazo[2,1-b]Chalcogenazoles", p-345-345. In: In Blucher Chemistry Proceedings, São Paulo, v. 1, n. 1, Setembro.2013. São Paulo: Blucher, 2013.
ISSN 23184043, DOI 10.5151/chempro-14bmos-R0345-2