A Review on Synthesis, Characterization Methods and Biological Activities of Semicarbazone, Thiosemi-Carbazone and Their Transition Metal Complexes

Fekadu Muleta

doi:10.7176/jnsr/9-17-04

Abstract

Semicarbazones and thiosemicarbazones are compounds obtained by condensation of Semicarbazides and thiosemicarbazide with suitable aldehydes or ketones. They are potent intermediates for the synthesis of pharmaceutical and bioactive materials and thus, they are used extensively in the field of medicinal chemistry. The development of new beneficial bioactive compounds exhibiting different biological activities is one of the crucial aims in medicinal and bioinorganic chemistry. Semicarbazones, thiosemicarbazones and their derivatives have been evaluated as antibacterial, antifungal, antioxidant, antiviral, radical scavenging, antitubercular, antitumor and anticancer therapeutics especially when bind to transition metals. Their biological activities are considered to be related to their ability to form chelates with metals. The structures of the compounds have been characterized on the basis of their IR and 1H-NMR data. Studies have been conducted on compounds bearing –N=N-, -N-C=S, and -CH=N- as pharmacophore. Accordingly by considering this biological potential herein, the synthesis root of some of these derivatives and complexes are reviewed as for biological activities and is aim to organize the different biological activities of some synthesized semicarbazone and thiosemicarbazone derivatives with transition metals. Keywords: Semicarbazone, thiosemicarbazones, Metal Complexes, antibacterial, antifungal and anticancer therapeutics. DOI : 10.7176/JNSR/9-17-04 Publication date :September 30 th 2019

Highlights

Semicarbazones and thiosemicarbazones are important compounds obtained by condensation of Semicarbazides with suitable aldehydes or ketones
Due to their carcinogenic properties the use of nitrofurans is prohibited within the EU in animal breeding (Commission Regulation 37/2010) to harmonize the detection of semicarbazide a Minimum Required Performance Limit (MRPL) of 1 μg/kg is set within the EU (Commission Decision 2003/181)
This review has dealt with an extensive literature study relating semicarbazone and thiosemicarbazone and their transition metal complex

Summary

INTRODUCTION

Semicarbazones and thiosemicarbazones are important compounds obtained by condensation of Semicarbazides with suitable aldehydes or ketones. Semicarbazone and thiosemicarbazone ligands usually coordinate to transition metals usually through their oxygen, nitrogen, and sulphur donor atoms in their (N, S) bidentate form or (N, N, S or O, N, S) tridentate form, to form metallic complexes[3,4]. Semicarbazones and thiosemicarbazones have a considerable interest in the field of chemistry and biology due to their antibacterial, antifungal[6], antimalarial and antiviral[7] activities through binding to metals in cells[8] They behave as chelating ligands containing donor imines groups which react with transition metal vacant d-orbital giving complexes. The chemistry of manganese in various oxidation states in various combinations of nitrogen and oxygen donor ligands like semicarbazone and thiosemicarbazone is currently witnessing intense biological activity[36]. CHEMICAL BONDING NATURE OF SEMICARBAZONES AND THIOSEMI-CARBAZONE WITH TRANSITION METALS The raw material for the synthesis of semicarbazone and thiosemicarbazone is semicarbazides, the compound prepared by treating urea with hydrazine as[37]: OC(NH2)2 + N2H4 → OC(NH2)(N2H3) + NH3 Structures

Urea hydrazine

Schiff Base

SH N

Benzaldehyde Thiosemicarbazone Derivatives

CONCLUSION