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

Synthesis of Fluorine-Containing Poly(phenylamino)-1,4-naphthoquinones

“…Unlike previously reported [1] reaction of 2-X-pentafluoro-1,4-naphthoquinones (X = BuNH, Et 2 N) with alkylamines in dioxane, nucleophilic substitution of fluorine atom in quinone I occurs mainly at the α-position of the benzene fragment. Therefore, stabilization of transition state in the substitution reaction with aniline (which is a stronger NH acid than alkylamines) may be contributed to an appreciable extent by coordination of hydrogen atom of the amino group to oxygen.…”

“…In contrast, the reaction of 2,5,8-tris(butylamino)-3,6,7-trifluoro-1,4-naphthoquinone (IIIa) with butylamine gave 2,5,6,8-tetrakis-(butylamino)-3,7-difluoro-1,4-naphthoquinone as a result of fluorine replacement in the aromatic ring [1]. Presumably, the observed change of the relative reactivity of the benzene and quinoid fragments is related to sharp weakening of electron-donating effect of the RNH substituent in going from quinone IIIa (R = Bu) to II (R = Ph), though replacement of fluorine at the quinoid double C=C bond is likely to be more sensitive to the neighboring substituent as compared to the replacement in the benzene ring.…”

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SHORT COMMUNICATIONS2-X-Substituted pentafluoro-1,4-naphthoquinones (X = BuNH, Et 2 N, MeO) are readily converted into the corresponding di-and polysubstituted quinones via nucleophilic replacement of fluorine by the action of aliphatic amines R 1 R 2 NH (R 1 R 2 N = BuNH, EtNH, Et 2 N) [1]. When X = BuNH or Et 2 N, nucleophilic attack is directed at the aromatic ring to give products of replacement of one to three fluorine atoms in that ring.

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“…Goryunov, V.D. Shteingarts, 2010, published in Zhurnal Organicheskoi Khimii, 2010 [1] for double defluorination of quinone I).…”

“…Signals in the 19 F NMR spectra were assigned by analogy with the corresponding fluorinated butylamino-1,4-naphthoquinones [1]. Quinones II-IV displayed in the 19 F NMR spectra multiplets in the region δ F 27.2-28.3 ppm, which were assigned to the 3-F atom; the 3-F signal in the spectrum of initial quinone I is located at δ F 28.1 ppm [3].…”