Behaviour of some newly synthesized substituted 1,2,4-triazoline-3-thiones in sulfuric acid media

Mirjana Jankulovska, Ilinka Spirevska, Katica Čolančevska-Ragenović

Abstract


The protonation process of some newly synthesized substituted 1,2,4-triazoline-3-thiones (4-butyl-5-octyl-2,4- dihydro-3H-1,2,4-triazoline-3-thione, 4-allyl-5-octyl-2,4-dihydro-3H-1,2,4-triazoline-3-thione, 4-phenyl-5-octyl-2,4- dihydro-3H-1,2,4-triazoline-3-thione) was investigated in aqueous sulfuric acid solutions, using the ultraviolet spectrophotometric method, at a room temperature. The acid-base equillibria were characterized qualitatively and quantitatively. The method of characteristic vector analysis (CVA) was used to reconstruct the experimental spectra. The protonation process, most likely occurs on the thiourea fragment of the 1,2,4-triazoline-3-thione ring. The pKBH + values were calculated using several methods: the Hammett acidity function method, Bunnett and Olsen, Tissier and Tissier (Bunnett and Olsen, Yates), Marziano, Cimino and Passerini, and the “Excess acidity" function method (Cox and Yates). There is a good agreement between the pKBH + values determined with these different methods.


Keywords


4-butyl-5-octyl-2,4-dihydro-3H-1,2,4-triazoline-3-thione; 4-allyl-5-octyl-2,4-dihydro-3H-1,2,4-triazoline- 3-thione; 4-phenyl-5-octyl2,4-dihydro3H-1,2,4-triazoline-3-thione; UV spectrophotometry; protonation constants

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References


A. R. Jalilian, S. Sattari, M. Bineshmarvasti, A. Shafiee, M. Daneshtalab, Synthesis and in vitro antifungal and cytotoxicity evaluation of thiazolo-4H-1,2,4-triazoles and 1,2,3-thiadiazolo-4H-1,2,4-triazoles-1,2,4-4H-triazolesthiazoles- 1,2,3-thiadiazoles, Arch. der Pharmazie, 333, 347–354 (2000).

N. Guelerman, S. Rollas, M. Uelgen, Synthesis and in vitro microsomal metabolism of 4-ethyl-5-(4-fluorophenyl)- 2,4-dihydro-3H-1,2,4-triazole-3-thione and its potential metabolites, Boll. Chim. Farm., 137 (5), 140– 143 (1998).

A. R. Katritzky, C. W. Rees, Comprehensive Heterocyclic Chemistry, Vol. 5, Pergamon Press LTD, London, 1984.

L. Arman-Zubi_, N. Periši_-Jani_, M. Lazarevi_, A study of the behaviour of some substituted 1,2,4-triazoline-3- thiones in different media, J. Serb. Chem. Soc., 65 (9), 619–630 (2000).

K. C. Ragenovic, V. Dimova, V. Kakurinov, D. M. Gabor, Synthesis of 1-nonanoyl/octadecanoyl 1-4-substituted thiosemicarbazides and substituted 1,2,4-triazoles as biological active compounds, J. Hetrocyclic Chem., 40, 905–908 (2003).

L. P. Hammett, A. J. Deyrup, A series of simple basic indicators. I. The acidity functions of mixtures of sulfuric and perchloric acids with water, J. Am. Chem. Soc., 54, 2721–2739 (1932).

H. C. Brown, P. W. R. Schleyer, The Non-Classical Ion Problem, Plenum Press, New York, 1977.

J. T. Edward, I. Lantos, G. D. Derdall, S. C. Wong, An acidity function based on thiocarbonyl indicators, Can. J. Chem., 55, 812–821 (1977).

J. F. Bunnett, F. P. Olsen, Linear free energy relationship concerning equilibria in moderately concentrated mineral acids, Can. J. Chem., 44, 1899–1916 (1966).

M. A. Paul, F. A. Long, H0 and related acidity functions, Chem. Rev., 57, 1–45 (1957).

M. J. Jorgenson, D. R. Harrter, A critical Re-evaluation of the Hammett Acidity Function at Moderate and High Acid Concentrations of Sulfuric Acid. New H0 Values Based Solely on a Set of Primary Aniline Indicators, J. Am. Chem. Soc., 85, 878–883 (1963).

R. A Cox, K. Yates, Acidity functions: an update, Can. J. Chem., 61, 2225–2243 (1983).

C. Tissier, M. Tissier, Propriétés acido-basiques des amides et thioamides, Bull. Soc. Chim. Fr., 2109–2117 (1972).

K. Yates, R. A. McClelland, Mechanisms of Ester Hydrolysis in Aqueous Sulfuric Acids, J. Amer. Chem. Soc., 89, 2686–2692 (1967).

N. C. Marziano, G. M. Cimino, R. C. Passerini, The MC Activity Coefficient Function for Acid-Base Equillibria. Part I. New Methods for Estimating pKa Values for Weak Bases, J. Chem. Soc. Perkin Trans. II, 1915–1926 (1973).

R. A Cox, K. Yates, Excess Acidities. A Generalized Method for the Determination of Basicities in Aqueous Acid Mixtures, J. Am. Chem. Soc., 100, 3861–3867 (1978).

A. Albert, E. P. Serjeant, The Determination of Ionization constants, Chapman, London, 1971.

T. E. Edward, S. C. Wong, Ionization of Carbonyl Compounds in Sulfuric Acid. Correction for Medium Effects by Characteristic Vector Analysis, J. Am. Chem. Soc., 99, 4229–4232 (1977).

C. T. Davis, T. A. Geissman, Basic Dissociation Constants of Some Substituted Flavones, J. Am. Chem. Soc., 76, 3507–3511 (1954).




DOI: http://dx.doi.org/10.20450/mjcce.2006.276

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