Mono/double 3-methoxypropan-1-amine substituted pyridone azo dyes having isomeric ortho/para-aminobenzoic acids and corresponding methyl esters components
| Autor: | Wei Huang, Xiao-Lei Zhao, Hui-Fen Qian, Yuan-Yuan Wang |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
chemistry.chemical_classification
Process Chemistry and Technology General Chemical Engineering Carboxylic acid Hydrazone 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Medicinal chemistry Tautomer 0104 chemical sciences chemistry.chemical_compound Deprotonation chemistry Pyridine Amine gas treating Diazo 0210 nano-technology Benzoic acid |
| Zdroj: | Dyes and Pigments. 153:44-52 |
| ISSN: | 0143-7208 |
| DOI: | 10.1016/j.dyepig.2018.01.054 |
| Popis: | Ortho/para-aminobenzoic acids and corresponding methyl esters were selected as the diazo components to couple with two mono functional group transformation (FGT) precursors with different pyridine N-substituted groups [1-ethyl-6-((3-methoxypropyl)amino)-4-methyl-2-oxo-1,2-dihydropyridine-3-carbonitrile and 1-(3-isopropoxypropyl)-6-((3-methoxypropyl)amino)-4-methyl-2-oxo- 1,2-dihydropyridine-3-carbonitrile] and one double FGT precursor [2,6-bis((3-methoxypropyl)amino)-4-methylnicotinonitrile], so as to produce a series of isomeric pairs of heterocyclic azo dyes. In comparison with conventional 2,6-pyridone based hydrazone dyes bearing the same ortho/para-aminobenzoic acids and corresponding methyl esters azo components, the pH stability of synthesized mono and double FGT azo dyes has been improved to different extents because of the removal of the active hydrazone proton via 3-methoxypropylamine substitution. Among them, double FGT azo dyes with methyl ester units show extremely high pH stability, but the ones with benzoic acid groups exhibit low pH stability due to the presence of carboxylic acid proton. In contrast, methyl ester involved mono FGT products display less pH stability (pH ˜ 10) owing to intra-ring azo-keto ⇌ azo-enol tautomerism under strong alkaline condition. It is noted that two distinguishable deprotonated processes could be observed for mono FGT products with benzoic acid groups, and two-step deprotonation mechanism is proposed by forming monovalent and bivalent anions under weak and strong alkaline conditions involving intra-ring azo-keto ⇌ azo-enol tautomerism. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect