Synthesis and antimicrobial activity of novel 2-Methyl-3-(1′3′4′-Thiadiazoyl)-4-(3h) Quinazolinones

Abstract

With a view to explore the versatile lead molecule 4(3H)-quinazolinones, a series of novel 2-methyl-3-(1'3'4' thiadiazoyl)-4-(3H) quinazolinones have been synthesised by reacting 2-amino-5-aryl/alkyl-1'3'4'-thiadiazoyl with 2-substituted benzoxazin-2-one. The designed compounds (5a-f) were screened in vitro for antibacterial activity on Staphylococcus aureus, Bacillus subtilis, and Escherichia coli. Antifungal activity was screened against Candida albicans, Aspergillus niger, and Curvularia lunata. Synthesised compounds exhibited both antibacterial and antifungal activity. Quinazolinone is a versatile lead molecule for designing potential bioactive agents. 4(3H)-Quinazolinone and its derivatives have been reported to exhibit analgesic, anaesthetic, antibacterial, anticancer, anticonvulsant, antimicrobial, antihypertensive, antiinflammatory, diuretic, muscle-relaxant, sedative, diuretic, CNS-depressant, and tranquilizer properties 1-6. We have already reported the biological activities of 1, 3, 4-thiadiazoles, including antimicrobial activities 7-8. This work was undertaken with a view to explore the possibility of antimicrobial activity in the present nucleus, which has both 4(3H)-quinazolinone and 1'3'4'-thiadiazoles in it. Six new 2-methyl-3-(1'3'4'-thiadiazoyl)-4(3H)-quinazolinones were synthesised and evaluated for their antimicrobial and antifungal activity. Anthranilic acid reacts with acetic anhydride and acetic acid to form corresponding 2-methylbenzoxazin-2 one by N-acylation, followed by dehydrative cyclization mechanism 9. The 2-methylbenzoxazin-2-ones condensed with the primary amino groups of 1'3'4'-thiadiazolyl group (aromatic and aliphatic) to form 2-methyl-3-(1'3'4'-thiadiazoyl)-4(3H) quinazolinones. Melting points were determined in open glass capillary and are uncorrected. The purity was checked by TLC using silica gel G as stationary phase and hexane: ethanol: chloroform (1:3:6) as mobile phase. The structure of the synthesised compounds were

Synthesis, Molecular Docking, In Silico ADME Predictions, and Toxicity Studies of N-Substituted-5-(4-Chloroquinolin-2-yl)-1,3,4-Thiadiazol-2-Amine Derivatives as COVID-19 Inhibitors

“…The quinoline ring has diverse activities, such as antimicrobial [3], anti-inflammatory [4], antituberculosis [5], antimalarial [6], antihypertensive [7], antibiotic [8], antiHIV [9] and tyrokinase PDGF-RTK inhibiting agents [10]. Also, 1,3,4-thiadiazole is a nitrogen containing compounds show a broad spectrum of pharmacological activities [11][12][13][14][15]. We synthesized N-substituted-5-(4chloroquinolin-2-yl)-1,3,4-thiadiazol-2-amine derivatives in order to investigate their biological activities, but as a result of the significant disruption that is being caused by the COVID-19 pandemic we couldn't study their biological activities in laboratory so we calculated it theoretically.…”