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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.

The new acylated indole alkaloid glucoside indole-3-carboxylic acid-(6'-O-caffeoyl)-β-D-glucoside 1 has been isolated from the ethyl acetate (EtOAC) extract of Saccocalyx satureioides Coss. & Dur. (Lamiaceae) together with eight known secondary metabolites 2-9. Two indoles 2 and 3, five methylated flavone aglycones 4-8 and one monoterpene glucoside 9 were reported for the first time in the genus Saccocalyx. The structural elucidation of these compounds was accomplished by spectroscopic methods including 1 D (1H and 13C) and 2 D (COSY, HSQC and HMBC) NMR techniques, and mass spectrometry, and by comparison with literature data. Light petroleum, EtOAc, chloroform and n-butanol (n-BuOH) extracts of S. Satureioides were screened for their antioxidant activity using DPPH radical scavenging and β-carotene bleaching methods. The antibacterial activity of these extracts indicates that n-BuOH and EtOAc extracts possess the strongest activity.

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.

A new series of diverse 1,2,3-triazole-acridinedione/xanthenedione and 1,2-isoxazole-acridinedione/xanthenedione heterocyclic hybrids have been synthesized via 1,3-dipolar coupling reaction of N/O-substituted-acridinedione-alkyne or O-substituted-xanthenedione-alkyne substrates with various aromatic azides or oximes. In all cases, the cycloaddition is totally regioselective. The chemical structures of the synthesized compounds are determined using 2D NMR and are further confirmed by single-crystal X-ray diffraction analysis. Preliminary in vitro cytotoxic assays on two human breast cancer cell lines (MDA-MB-231, T47-D) and one prostate cancer cell line (PC3) are performed on some selected compounds. The most active O-1,2,3-triazole-xanthenedione hybrid displays the best cytotoxicity effects with IC50 ≤ 20 μM in breast cancer and IC50 = 10 μM in prostate cancer cell lines.

Novel series of triazole-benzimidazole-chalcone hybrid compounds have been synthesized via click chemistry, between different azide derivatives and substituted benzimidazole terminal alkynes bearing a chalcone moiety. The starting alkynes are prepared via base-catalysed nitrogen alkylation of pre-synthetized benzimidazole-chalcone substrates. All the intermediates as well as the final products are fully characterized by 1D and 2D NMR and mass spectrometry techniques. HMBC correlations permits the identification of a unique 1,4-disubstitued triazole-benzimidazole-chalcone isomer. Evaluation of the anti-proliferative potential in breast and prostate cancer cell lines showed that the presence of chloro substituents at the chalcone ring of the triazole-benzimidazole-chalcone skeleton enhanced the cytotoxic effects. The benzyl group linked to the 1,2,3-triazole moiety provides more antiproliferative potential.