Novel 2-amino-1,3,4-thiadiazoles and their acyl derivatives: Synthesis, structural characterization, molecular docking studies and comparison of experimental and computational results

Abstract

This study aims to synthesize and characterize compounds containing 2-amino-1,3,4-thiadiazole and compare experimental results to theoretical results. For this purpose, firstly mono, di and tetra 2-amino-1,3,4-thiadiazole compounds (2a-c, 14, 20 and 25) were synthesized in relatively high yields (74-87%). The target compounds (3-11, 15-17, 21-23 and 26-28) were then synthesized in moderate to high yields (65-85%) from the reactions of 2-amino-1,3,4-thiadiazole compounds with various acyl chloride derivatives. The structures of all synthesized compounds were elucidated by IR, H-1 NMR, C-13 NMR, elemental analyses and mass spectroscopy techniques. The structures of 2b (C9H8N4O2S) and 2c (C11H13N3O2S) were also elucidated by X-ray diffraction analysis. Lastly, IR spectrum, H-1 NMR and C-13 NMR chemical shift values, frontier molecular orbital (FMO) values of these molecules containing heteroatoms were examined using the Becke-3- Lee-Yang-Parr (B3LYP) method with the 6-31G(d) basis set. Two different molecular structures containing 2-amino-1,3,4-thiadiazole (2b, 2c) were used in our study to examine these properties. Also, compounds 2b and 2c form a stable complex with beta-Lactamase as can be understood from the binding affinity values and the results show that the compound might inhibit the beta-Lactamase enzyme. It was found that theoretical and experimental results obtained in the experiment were compatible with each other and with the values found in the literature. (C) 2016 Elsevier B.V. All rights reserved.