DETERMINATION AND EVALUATION OF ACIDITY CONSTANTS OF SOME IMIDAZOLE AND THIAZOLE LINKED ACETAMIDE COMPOUNDS
Abstract
In this work, the effect of substituents on the acidity constants of some acetamide derivatives was investigated. The acidity constants of nine acetamide derivatives were determined at 25 °C using a UV spectrophotometric method. When the molecules possessed different substituents the values of the acidity constants changed from 6.01 to 8.22 for the first protonation and from 3.07 to 4.73 for the second protonation. The first protonation under these circumstances was observed to occur on the nitrogen atom of the 2-mercaptoimidazole ring. The second protonation was observed to occur on the nitrogen atom of the thiazole ring.
Keywords
İmidazol,Tiyazol; Asetamit; Protonlanma yolları; UV spektroskopi; pKa
References
- Foulon C, Duhal N, Lacroix-Callens B, Vaccher C, Bonte JP, Goossens JF. Determination of pK(a) values of benzoxa-, benzothia- and benzoselena-zolinone derivatives by capillary electrophoresis - Comparison with potentiometric titration and spectrometric data. Eur J Pharm Sci 2007; 31: 165-171.
- Corona-Avendano S, Alarcon-Angeles G, Rojas-Hernandez A, Romero-Romo MA, Ramirez-Silva MT. Study on the stability of adrenaline and on the determination of its acidity constants. Spectrochim Acta A 2005; 61: 305-311.
- Alizadeh K, Ghiasvand AR, Borzoei M, Zohrevand S, Rezaei B, Hashemi P, Shamsipur M, Maddah B, Morsali A, Akhbari K, Yavari I. Experimental and computational study on the aqueous acidity constants of some new aminobenzoic acid compounds. J Mol Liq 2009; 149: 60-65.
- Alizdeh K, Rezaei B, Maddah B. Spectrophotometric determination of aqueous acidity constants of three azo dyes. Cent Eur J Chem 2010; 8: 392-395.
- Niazi A, Yazdanipour A, Ghasemi J, Amini A, Bozorgzad S, Kubista M. Spectrophotometric investigation of the acidity constants of fluorescein in various water-organic solvent media. Chem Eng Commun 2008; 195: 1257-1268.
- Bordbar M, Faal AY, Ahari-Mostafavi MM, Gharagozlou M, Fazaeli R. Multi-wavelength spectrophotometric determination of acidity constants of some salicylaldimine derivatives. J Mol Liq 2013; 178: 70-77.
- Huang Y, Liu LH, Liu WH, Liu SG, Liu SB. Modeling Molecular Acidity with Electronic Properties and Hammett Constants for Substituted Benzoic Acids. J. Phys. Chem. A2011; 115: 14697-14707.
- Diaz D, Ford KA, Hartley DP, Harstad EB, Cain GR, Achilles-Poon K, Nguyen T, Peng J, Zheng Z, Merchant M, Sutherlin DP, Gaudino JJ, Kaus R, Lewin-Koh SC, Choo EF, Liederer BM, Dambach DM.. Pharmacokinetic drivers of toxicity for basic molecules: Strategy to lower pKa results in decreased tissue exposure and toxicity for a small molecule Met inhibitor. Toxicol Appl Pharm 2013; 266: 86-94.
- Duran, M, Canbaz MC. pKa Determination of Newly Synthesized N-(benzothiazole-2-yl)-2-(4,5- dimethyl-1-(phenylamino)-1H-imidazol-2-ylthio) acetamide derivatives. Ind Eng Chem Res 2013; 52: 8355-8360.
- Öğretir C, Demirayak S, Tay NF, Duran M. Determination and evaluation of Acid Dissociation Constants of Some Substituted 2-Aminobenzothiazole Derivatives. J Chem Eng Data 2008; 53: 422- 426.