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The synthesis and biological assessment of 2,5-disubstituted-1,3,4-oxadiazole derivatives from benzo hydrazide and amino acids as novel potential antioxidant and antibacterial agents have been reported. The structures of the new compounds were characterized by physicochemical properties and spectral methods. The synthesized compounds were screened for their in vitro antibacterial activity against three Gram-positive bacterial strains, namely Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 14579, Listeria innocua ATCC 33090, and two Gram-negative bacterial strains, namely Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922, and antifungal activity against Candida albicans ATCC 10231 in comparison with Amoxicillin, Tetracycline, Gentamicin and Oxacillin as standards. Most of the compounds have excellent efficacy, and some of them, such as 5i, 5g, 5d, 5c, and 5j can inhibit their activity better or very close to that of Amoxicillin, Tetracycline, Gentamicin, Oxacillin used as standards. Compounds 5b and 5i provided good results against L. innocua with inhibition values of IZ = 14 mm and IZ = 22 mm, respectively, while the rest of the compounds and antibiotics were unable to inhibit it. Compounds 5c, 5d, 5g and 5j showed excellent activity against C. albicans with values between 31 mm and 34 mm. These results were better than all the standards used. The MIC value (25 µg/ml) for derivatives 5(c-e), 5g and 5(i-j) against B. cereus represent the best activity of the tested compounds. All the target compounds were also screened for radical scavenging antioxidant activities by DPPH, FRAP, and TAC assays and found to be excellent antioxidant agents. According to the results, it was observed that most derivatives synthesized showed excellent activity with a concentration of 250 µg/ml as an antioxidant agent (76 % < RSA

The synthesis and biological assessment of 2,5-disubstituted-1,3,4-oxadiazoles derivatives from amino acids as new potential antibacterial and antioxidant agents have been reported. The structures of the new synthesized compounds were characterized based on physicochemical and spectral data UV–Visible, IR, 1HNMR, 13CNMR. All the target compounds were screened for their in vitro antibacterial activity against three Gram-positive bacterial strains, namely Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 14579, Listeria innocua ATCC 33090, and two Gram-negative bacterial strains, namely Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922, and antifungal activity against Candida albicans ATCC 10231 in comparison with Amoxicillin, Tetracycline, Gentamicin and Oxacillin. The only compound 1-{(4S)-4-amino-4-[5-(2-hydroxyphenyl)-1,3,4-oxadiazol-2-yl]butyl}guanidine 5e with the amine radical that showed excellent results against all bacteria, particularly against L. innocua (IZ = 12 mm), has excellent antifungal activity (IZ = 32 mm). The compounds 2-[5-(1-amino-3-methylbutyl)-1,3,4-oxadiazol-2-yl]phenol 5b and 2-[5-(pyrrolidin-2-yl)-1,3,4-oxadiazol-2-yl]phenol 5j have excellent activities (IZ = 27 and IZ = 28 mm, respectively) against B. cereus and P. aeruginosa. Compounds 2-{5-[(1R)-1-amino-2-sulfanylethyl]-1,3,4-oxadiazol-2-yl}phenol 5c, 2-{5-[(1S)-1-amino-3-(methylsulfanyl)propyl]-1,3,4-oxadiazol-2-yl}phenol 5d with the sulfur radical, 3--[5-(2-3-amino hydroxyphenyl)-1,3,4-oxadiazol-2-yl]propanamide 5g with the amide radical, 5j with the amino radical, and 4-amino-4-[5-(2-hydroxyphenyl)-1,3,4-oxadiazol-2-yl]butanoic acid 5k gave good results against B. cereus, where 19 mm

This study presents a novel method for synthesizing 1,4-disubstituted 1,2,3-triazole derivatives through a one-pot, multi-component addition reaction using flower-like Cu2O microbeads as a catalyst. The flower-like Cu2O microbeads were synthesized using an aqueous extract of Artimisia Campestris L. This extract demonstrated the capability to reduce and stabilize Cu2O particles during their initial formation, resulting in the formation of a porous flower-like morphology. These Cu2O microbeads exhibit distinctive features, including a cubic close-packed (ccp) crystal structure with an average crystallite size of 22.8 nm, bandgap energy of 2.7 eV and a particle size of 6 µm. Their catalytic activity in synthesizing 1,4-disubstituted 1,2,3-triazole derivatives was investigated through systematic exploration of key parameters such as catalyst quantity (1, 5, 10, 15, 20, and 30 mg/mL), solvent type (dimethylformamide/H2O, ethanol/H2O, dichloromethane/H2O, chloroform, acetone, and dimethyl sulfoxide), and catalyst reusability (four cycles). The Cu2O microbeads significantly increased the product yield from 20% to 85.3%. The green synthesis and outstanding catalytic attributes make these flower-like Cu2O microbeads promising, efficient, and recyclable catalysts for sustainable and effective chemical transformations.

Four novel heterocyclic1,3,4-oxadiazole, 1,2,4-triazole derivatives, namely: 5-[1-amino-3-(methylsulfanyl)propyl]-1,3,4-oxadiazole-2(3H)-thione (4), 4-amino-5-[1-amino-3-(methylsulfanyl)propyl]-4H-1,2,4-triazole-3-thiol (5), 1-amino-3-[1-amino-3-(methylsulfanyl)propyl]-1H-1,2,4-triazole-5-thiol (7), and 5-[1-amino-3-(methylsulfanyl)propyl]-1H-1,2,4-triazole-3-thiol (9) have been synthesized from l-methionine and characterized by different spectroscopic techniques (FT-IR, UV–Vis, 1H NMR, 13C NMR and MS). Complex formation with Hg++ and Fe+++ ions were formed from the four heterocyclic 4, 5, 7 and 9. The antimicrobial activities for synthetic intermediates and final four products were assisted using paper disk diffusion method against Gram-negative bacteria: Escherichia coli, Pseudomonas aeroginosae and Gram-positive bacteria: Staphylococus aureus 25923, Staphylococus aureus 43300 and showed variant activity against some of the microorganisms tested.

Four novel diazole-thiol derivatives namely: 5-(1-amino-2-sulfanylethyl)-1,3,4-oxadiazole-2(3H)-thione 6, 4-amino-5-(1-amino-2-sulfanylethyl)-4H-1,2,4-triazole-3-thiol 7, 1-amino-3-(1-amino-2-sulfanylethyl)-1H-1,2,4-triazole-5-thiol 8, and 5-(1-amino-2-sulfanylethyl)-1H-1,2,4-triazole-3-thiol 9 have been synthesized from l-Cysteine and characterized by IR, 1H NMR, 13C NMR and GC–MS. Complex formation with Ni(II) and Cu(II) ions with four diazole-thiol derivatives of l-Cysteine were formed and isolated. The final synthetic products (6–9) and their corresponding Ni(II) and Cu(II) complexes (6a,a′-9a,a′) were tested against Gram-negative bacteria: Escherichia coli, Pseudomonas aeroginosae and Gram-positive bacteria: Staphylococus aureus 25923 and showed no biological activity. While Ni(II) and Cu(II) complexes of 7–9 exhibited appreciable activity against tested microorganisms. The outstanding results is that the Cu(II)-complexes 8a′ and 9a′ showed their (MIC) activity on similar organisms at very low concentrations (5 µg/ml) which is in fact lower concentration than what had been reported on other relative compounds.