3,5-dinitro-4-methoxyaminobenzoic acid and its derivatives

The synthesis of the 3,5-dinitro-4-methoxyaminobenzoic acid (1) and its derivatives (2-6, 7c and 8c) was studied. The two pK(a) values of the acid 1 (4.50 and 9.75) have been determined; both the mono- and the di-potassium salts (2 and 3, respectively) were prepared. The methyl ester 4 can be synthe...

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Bibliographic Details
Published inRevue roumaine de chimie Vol. 44; no. 4; pp. 333 - 340
Main Authors Covaci, IC, Constantinescu, T, Caproiu, MT, Draghici, C, Ionita, P, Luca, C, Stanciuc, G, Maganu, M, Balaban, AT
Format Journal Article
LanguageEnglish
Published BUCHAREST Editura Academiei Romane 01.04.1999
Subjects
Chemistry
Chemistry, Multidisciplinary
Physical Sciences
Science & Technology
EQUILIBRIA
AMINYL RADICALS
SPECTRA
FACTORS AFFECTING STABILITY
EPR
FREE-RADICALS
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Summary:The synthesis of the 3,5-dinitro-4-methoxyaminobenzoic acid (1) and its derivatives (2-6, 7c and 8c) was studied. The two pK(a) values of the acid 1 (4.50 and 9.75) have been determined; both the mono- and the di-potassium salts (2 and 3, respectively) were prepared. The methyl ester 4 can be synthesised from the dipotassium salt 3 and methyl iodide in stoichiometric amounts, while with an excess of methyl iodide, methylation occurs both at the amino and the carboxy groups (trimethyl derivative 6). The ester 4 has one pK(a) 8.60; its potassium salt 5 gives with crown ether 18-C-6 a blue complex. The ester 4 reacts with an excess of DPPH (free radical) affording the blue betainic compound (1-picryl-2-[4-(4-carbomethoxy-2,6-dinitrophenylamino)phenyl]-diazenium betaine) 7c; the betaine 7c is reduced with ascorbic acid affording the yellow-orange compound (1-picryl-2-phenyl-2-[4-(4-carbomethoxy-2,6-dinitrophenyl-amino)phenyl]-hydrazine) 8c. Electronic, H-1-NMR and (1)3C-NMR spectra are reported.
ISSN:0035-3930