Aminodefluorination of 2-X-pentafluoro-1,4-naphthoquinones (X = NHnBu, NEt2, and OMe)

Aminodefluorination of 2-n-butylamino- and 2-diethylaminopentafluoro-1,4-naphthoquinone by alkylamines HNR1R2 (NR1R2 = NHEt, NHnBu and NEt2) occurs at the 6- or 8-position and further, accordingly, at the 8- or at one of the 5- and 6-sites. The isomer ratio changes significantly in favor of a β-replacement product with solvent variation in the sequence: toluene < 1,4-dioxane < DMSO. n-Butylaminodefluorination of 2-methoxypentafluoro-1,4-naphthoquinone gives mixtures of fluorine substitution products both on the benzene and quinone rings.

Graphical abstractThe series of potentially bioactive polyfluorinated derivatives of 2-amino-1,4-naphthoquinone have been synthesized by mono- and dialkylaminodefluorination on benzene or quinone moiety of 2-n-butylamino-, 2-diethylaminopentafluoro- or 2-methoxyhexafluoro-1,4-naphthoquinone and the regioselectivity has been revealed as depending on a reagent, substituent and solvent nature.Figure optionsDownload full-size imageDownload as PowerPoint slide