- Acidity and basicity of primary N-phenylnitramines: Catalytic effect of protons on the nitramine rearrangement
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Para-substituted N-phenylnitramines were prepared either by oxidation of diazonium salts or by nitration under alkaline or acidic conditions. Isotopic [15N-NO2] labelling indicated that the bands characteristic of the N-nitro group appear in the 1318-1323 and 1585-1607 cm-1 regions. In the nitrogen NMR spectra, the nitramino group gives two resonances at -193 ± 3 (NH) and -32 ± 3 ppm (NO2). The chemical shifts in proton and carbon NMR spectra are predictable, based on increments and the additivity rule. The spectral data indicate the lack of conjugation between the nitramino group and another substituent bound to the ring. It seems to contradict the well-known fact that substituents strongly (ρ = 4) influence the rate of nitramine rearrangement. The acidities of primary N-phenylnitramines (3.77 A B ≈ 21) are extremely low. Consequently, addition of protons to an intact nitramine molecule, as the preliminary step of the rearrangement, seems to be improbable. Migration of the N-nitro group precedes protonation; the latter process facilitates transformation of intermediates into stable final products. Copyright
- Daszkiewicz, Zdzislaw,Spaleniak, Grzegorz,Kyziol, Janusz B.
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p. 115 - 122
(2007/10/03)
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- Fungicidal phenylnitramines and new phenylnitramines
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The present invention relates to novel methods for the protection of agricultural crops against plant pathogenic fungi comprising applying to the foliage of said crops a fungicidally effective amount of a compound selected from certain substituted phenylnitramines and certain novel salts of 2,3,5,6-tetrachlorophenylnitramine. The present invention further relates to certain novel substituted phenylnitramine and certain novel salts of 2,3,5,6-tetrachlorophenylnitramine and methods of preparation thereof.
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