Synthesis, Structural Characterization, and Biological Evaluation of Novel Substituted 1,3‐Thiazole Derivatives Containing Schiff Bases

Abstract

In this study, thiazole derivatives containing Schiff bases (7a, 7b, 7c, 7d, 7e, 7f, 8a, 8b, 8c, 8d, 8e, 8f, 9a, 9b, 9c, 9d, 9e, 9f) were synthesized in moderate to high yields (49–94%) using the Hantzsch reaction with thiosemicarbazone derivatives (5a, 5b, 5c) and 2‐bromo‐1‐phenylethanone derivatives (6a, 6b, 6c, 6d, 6e, 6f). The structures of synthesized compounds were elucidated by IR, 1H NMR, 13C NMR, elemental analyses, mass spectroscopy and X‐ray diffraction analysis techniques. Moreover, the synthesized compounds were tested for their in vitro antifungal activity and most of them exhibited moderate to good activity against Fusariumoxysporumf.sp. lycopersici.

Design, Synthesis, SAR and Molecular Modeling Studies of Novel Imidazo[2,1‐b][1,3,4]Thiadiazole Derivatives as Highly Potent Antimicrobial Agents

“…There have been significant increases in the synthesis of compounds having antimicrobial activities in recent years . However, the use of such compounds has been very limited due to drug resistance, high toxicity, various side effects and the deficiencies in biological activities.…”

“…There have been significant increases in the synthesis of compounds having antimicrobial activities in recent years. [1] However, the use of such compounds has been very limited due to drug resistance, high toxicity, various side effects and the deficiencies in biological activities. Medicinal chemists, therefore, put great efforts to synthesize new compounds having antimicrobial activities with minimum side effects, which can be used as a precursor or lead compound in the drug discovery.…”

“…[2][3][4][5][6] Furthermore, the synthesis of compounds including these bioactive groups with various biological activities is currently being studied. [7][8][9] These heterocyclic systems where the imidazole and 1,3,4-thiadiazole rings are fused with a bridgehead nitrogen atom are known as imidazo[2,1-b] [1,3,4]thiadiazoles. [10][11][12] Owing to the fact that imidazo[2,1-b] [1,3,4]thiadiazoles and their derivatives exhibit many biological activities such as antimicrobial, [13,14] antifungal, [15] antibacterial, [16][17][18] antiinflammatory, [19][20][21] antituberculosis, [22][23][24][25] analgesic, [26] diuretic [27] activities, the synthesis of these compounds and their derivatives increases gradually.…”

“…[10][11][12] Owing to the fact that imidazo[2,1-b] [1,3,4]thiadiazoles and their derivatives exhibit many biological activities such as antimicrobial, [13,14] antifungal, [15] antibacterial, [16][17][18] antiinflammatory, [19][20][21] antituberculosis, [22][23][24][25] analgesic, [26] diuretic [27] activities, the synthesis of these compounds and their derivatives increases gradually. [28,29] Besides being used as an anthelmintic drug, the fact that these compounds are bio-isostere of Tetramisole and its enantiomers Levamisole and Dexamisole [30,31] that are used as regulating and strengthening elements for immune system, has caused the anti-cancer activity studies to focus on imidazo [2,1-b] [1,3,4]thiadiazole derivatives. [32][33][34][35][36][37][38] It was reported that, apart from their biological activities, imidazo [2,1-b] [1,3,4]thiadiazole and their heterocyclic derivatives are also preferred in different industrial fields such as dye production.…”

“…

In this study, a novel series of phenyl substituted imidazo [2,1-b] [1,3,4]thiadiazole derivatives were synthesized, characterized and explored for antibacterial activity against Gram-negative Escherichia coli, Gram-positive Staphylococcus aureus and Bacillus subtilis and antifungal activity against Candida albicans. Most of the synthesized compounds exhibited remarkable antimicrobial activities, some of which being ten times more potent than positive controls.

…”