SYNTHESIS OF 1-ACYL-4-METALLYL-THIOSEMICARBASIDES WITH LONG ALKYL SUBSTITUENTS

Abstract

Thiosemicarbazide derivatives are increasingly attracting the attention of scientists due to their diverse biological activity. For example, substituted thiosemicarbazides are potent α-glucoxidase inhibitors, have antihelmintic action, as well as antituberculosis, antioxidant, and antimicrobial activity. Many metal complexes based on thiosemicarbazide-containing ligands exhibit antimicrobial properties. In addition, polysubstituted thiosemicarbazide derivatives are widely used in preparative organic chemistry as starting materials for the synthesis of heterocyclic compounds.
 This paper describes the method of production and physicochemical properties of five new 1-acyl-4-methyl-thiosemicarbazides. The synthesis was performed by the interaction of acid hydrazides with methyl isothiocyanate in ethanol under heating. The structure of the obtained compounds was confirmed based on 1H NMR spectroscopy data. The corresponding spectra were recorded in a solution of deuterated dimethyl sulfoxide on a Varian VXR 400 instrument.
 The PMR spectra of 2-R-N-methallylhydrazine-1-carbothioamides clearly indicate the introduction of a methallyl fragment. Thus, there is a doublet of the CH2NH group at 4.02 ppm. It is noted that the signal of the methylidene group of the methallyl fragment is manifested in the PMR spectrum in the form of a singlet at 4.73 ppm with a relative intensity of 2, as opposed to the expected splitting into two singlets with relative intensities of 1. A singlet with a relative intensity of 3 at 1.65 ppm corresponds to the methyl group of the methallyl fragment. Also, it can be clearly tracked the signals of the heptyl chain in the PMR spectrum (R = C7H15). Thus, the signals of the α-methylene and β-methylene groups are manifested in the form of a triplet at 2.12 ppm and a multiplet at 1.50 ppm, respectively. The terminal methyl group of the heptyl chain is manifested in the form of a triplet at 0.86 ppm with a relative intensity of 3. The signals of the other four methylene groups of the heptyl chain overlap and form a widened multiplet in the range of 1.25–1.29 ppm with a relative intensity of 8. Thus, in this work, the synthesis of new 1-acyl-4-methallyl-thiosemicarbazides with alkyl substituents was performed, and the 1H NMR spectra of the obtained compounds were analyzed.
 The obtained compounds are promising for use in synthetic organic chemistry (for the production of heterocyclic compounds), as well as ligands for the synthesis of complexes that will have biological activity.