- Steric hindrance to the syntheses and stabilities of 1,5- and 2,6-naphthalene N-permethylated diammonium salts
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A series of naphthalene-1,5- and 2,6-diamines and their N-methyl derivatives were synthesized and characterized. 1H NMR spectroscopy showed that an aqueous solution of naphthalene-2,6-di(NMe3I) (2) underwent considerable demethylation over a 24 h period after its initial preparation. Exchange of the iodide nucleophilic anion by the triflate non-nucleophilic counter-ion afforded a stable quaternary aminium salt. H/D α-position exchange in D2O solutions of naphthalene-2,6-di(NH2MeCl) (3·HCl) and naphthalene-2,6-di(NHMe2Cl) (4·HCl) with acidic +NH protons was observed, but not in those of naphthalene-2,6-di(NMe3I) or triflate (2 or 5). Exhaustive per-N-methylation of naphthalene-1,5-di(NMe2) (7) afforded only the mixed naphthalene-1-NMe3I-5-NHMe2I quaternary aminium-tertiary ammonium salt due to severe 1,8-type peri-strain.
- ?kalamera, Dani,Cao, Liping,Isaacs, Lyle,Glaser, Robert,Mlinari?-Majerski, Kata
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- Vapor pressures and phase transitions of a series of the aminonaphthalenes
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Vapor pressures of 1-aminonaphthalene, 1,8-diaminonaphthalene, 1,5-diaminonaphthalene, N,N-dimethyl-1-aminonaphthalene, 1,8-N,N,N,N',N'- tetramethyldiaminonaphthalene, and 1,5-N,N,N',N'-tetramethyldiaminonaphthalene have been determined by the transpiration method. The molar enthalpies of sublimation and the molar enthalpies of vaporization have been determined from the temperature dependence of the vapor pressure. Experimental vaporization and sublimation enthalpies were checked for internal consistency with help of available data on fusion enthalpies.
- Verevkin, Sergey P.,Georgieva, Miglena,Melkhanova, Svetlana V.
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- A simple and effective procedure for the N-permethylation of amino-substituted naphthalenes
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A wide range of amino-substituted naphthalenes can be N-permethylated by the system Me2SO4/Na2CO3/ H2O(alcohols) with good to excellent yields. Steric hindrance does not prevent the reaction. Some amines with electron-withdrawing groups, especially at nonconjugated positions, are also alkylated. The procedure allows the combination of a reduction (catalytic or by tin dichloride in acidic media) and a methylation in a one-pot process. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).
- Sorokin, Vladimir I.,Ozeryanskii, Valery A.,Pozharskii, Alexander F.
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- peri-naphthalenediamines: XXXIV. 1,4,5,8-Tetrakis(dimethylamino)naphthalene: Alternative approaches to synthesis
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New methods were proposed for synthesizing 1,4,5,8-tetrakis(dimethylamino)naphthalene with an overall yield of 4 to 12% to replace the known procedure ensuring an overall yield of 2%. Catalytic hydrogenation was shown to be inapplicable for preparation of polyaminonaphthalenes from nitro compounds having 3 or 4 nitro gruops in the α-positions. Nucleophilic amination of 1,5-dinitronaphthalene in the system NH2OH/NaOH/MeOH yields 1-amino-4-nitronaphthalene. The nitration of 1,5-bis(p-tolylsulfonylamino)-naphthalene leads to formation of 2,6-dinitro rather than 4,8-dinitro derivative, as it was believed formerly. This was confirmed by transformation of the latter into 1,2,5,6-tetrakis(dimethylamino)naphthalene. 3-Nitro, 2,6-dinitro, 2,6-diamino, and 2,4,6,8-tetranitro derivatives of 1,5-bis(dimethylamino)naphthalene, nitro and amino derivatives of 1,4,5-tris(dimethylamino)naphthalene, and 4,5-diamino-1,8-bis(methylamino)naphthalene were synthesized. By treatment with perchloric acid 1,4,5,8-tetrakis(dimethylamino)naphthalene was oxidized to 2,3-dihydroperimidinium salt.
- Sorokin,Ozeryanskii,Pozharskii
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- Modulating the ground- and excited-state oxidation potentials of diaminonaphthalene by sequential N-methylation
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A series of 1,5-diaminonaphthalene derivatives were synthesized, and characterized to provide ground- and excited-state electron donors of similar structure but varying potential. Electrochemical and spectroscopic properties of the series are reported and together illustrate two opposing consequences of alkyl substitution on the aryl amines. Inductive effects of methylation are evident from the decrease in ground-state oxidation potential for derivatives containing monomethylamino substituents. In contrast, steric effects seem to dominate the increase in the ground-state oxidation potential of derivatives containing dimethylamino substituents since the conformational constraints created by dimethylation suppress delocalization of the nonbonding electrons. Absorption and emission properties also respond to increasing levels of N-methylation, and the excited-state oxidation potentials of the parent 1,5-diaminonaphthalene and its monomethylamine derivatives (ca.-3.2 V) are approximately 200 mV lower than the corresponding dimethylamino derivatives (-3.0 V).
- Campbell, Neil P.,Finch, Amethist S.,Rokita, Steven E.
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