Reductive debromination of 1-methyl-2,4,5-tribromoimidazole mediated by dry tetramethylammonium fluoride in aprotic solvents

• Main Authors: Bastos Mônica M., Barbosa Jussara P., Pinto Angelo C., Kover Warner B., Takeuchi Yoshio, Boechat Núbia
• Format: Article
• Language: English
• Published: Sociedade Brasileira de Química 2001-01-01
• Series: Journal of the Brazilian Chemical Society
• Subjects: tribroimidazole; fluoroimidazole; reductive debromination
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532001000300015

The reaction of dry tetramethylammonium fluoride (TMAF) with 1-methyl-2,4,5-tribromoimidazole in different polar aprotic solvents was investigated. Products of reductive debromination were obtained rather than fluorine substitution, indicating that TMAF is strongly basic in such conditions. A reaction carried out in d6-DMSO showed that the solvent is the proton source. Dimethylformamide was less effective that DMSO, N,N-dimethylacetamide or N-methylpirrolidone as a proton donor and we were able to effect significant fluorination in this solvent.