hydrazone tautomers. The tautomeric state is not substantially influenced by nitro group substitution in the phenyl ring. Consequently, the studied compounds can be used as model tautomers in the NMR evaluation of the tautomeric state in various azo dyes in solution. According to the crystallographic data (obtained by us or available in the literature) the conclusions about the tautomerism of the studied
Synthesis of Newly Substituted Pyrazoles and Substituted Pyrazolo[3,4-<i>b</i>]Pyridines Based on 5-Amino-3-Methyl-1-Phenylpyrazole
作者:Talaat I. El-Emary
DOI:10.1002/jccs.200700072
日期:2007.4
10b was produced through reaction of 9 with acetophenone. Reaction of 1 with benzylidinemalononitrile afforded 11. New methods for preparation of 15 and 16 are described. The reaction of 8 with malononitrile, thio-semicarbazide, phenyl hydrazine and acetophenone afforded compounds 18-21. The reaction of 21 with malononitrile gave 22. Compounds 23-26 were produced upon reaction of 10a with malononitrile
Medium Effect on the Acid Dissociation Constants of Some Heterocyclic Azo Compounds
作者:Said A. Ibrahim、Nasr M. Rageh、Ahmed A. Mohamad、Youssif H. Ebead
DOI:10.1021/je9802165
日期:1999.5.1
The effect of different organic solvent + water mixtures on the aciddissociationconstants of protonated 5-amino-4-(arylazo)-3-methyl-1-phenylpyrazole derivatives were studied. The organic solvents used are methanol, ethanol, acetone, and dimethylformamide. The results obtained were discussed in terms of the solvent characteristics.The pKBH+ values of the dyes in question were determined and found
研究了不同的有机溶剂和水的混合物对质子化的5-氨基-4-(芳基偶氮)-3-甲基-1-苯基吡唑衍生物的酸解离常数的影响。使用的有机溶剂是甲醇,乙醇,丙酮和二甲基甲酰胺。讨论了所得结果的溶剂特性。p K BH确定了所讨论的染料的+值,发现该值取决于有机助溶剂的量和性质。p K BH的减少随着介质中有机溶剂量的增加, +值可以通过分散力而不是通过氢键来解释化合物的质子化形式的高稳定性。以及溶剂极化率和氢键相互作用对p K BH的影响+值,因此在所观察到的电荷转移带的光谱上已经进行了讨论。绝对p K BH尽管存在多个碱度中心,但每种化合物的+值也已讨论过。
Michaelis, Justus Liebigs Annalen der Chemie, 1905, vol. 339, p. 146