Nitroimidazoles, Part 2

Nitroimidazoles Part 10. Synthesis, crystal structure, molecular docking, and anticancer evaluation of 4-nitroimidazole derivatives combined with piperazine moiety

Piperazine-tagged imidazole derivatives 3a (symmetrical di-substituted piperazine) and 5-11 were synthesized through the combination of 4-nitroimidazole derivatives with piperazine moiety. The structural characterization was done by different physical and spectral techniques like NMR (¹H and ¹³C) and mass spectrometry. The constituency of compound 3a was confirmed by X-ray structural analyses. All compounds were assessed for their antiproliferative inhibition potency against five human cancer cell lines namely MCF-7, PC3, MDA-231, A549 and Fibro dental. Compound 5 was found to be the most potent anticancer agents against MCF-7 cell line with IC₅₀ values of (1.0 ± 0 µm) and against PC3 with IC₅₀ value of (9.00 ± 0.028 µm). The molecular docking of compound 5 had been studied, and the results revealed that the newly designed 4-nitroimidazole combined with piperazine moiety derivatives bond to the hydrophobic pocket and polar contacts with high affinity.

Design, synthesis and antimicrobial assessments of aminoacetylenic-piperazine nitroimidazole hybrid compounds

A new series of aminoacetylenic nitroimidazole piperazine hybrid compounds were prepared via three-component reaction. Mannich-type reaction was utilized to couple the nitroimidazole containing propargylic moiety with secondary amines and formaldehyde in the presence of Cu (I) catalyst. The newly synthesized molecules 10a-10w, were characterized an ambiguously through NMR and mass spectrometry. The prepared compounds were assessed in vitro for their antibacterial activity against selected gram-positive and gram-negative bacteria. All of the compounds had shown insignificant activities toward gram-negative bacteria. While compounds 10m, 10q, 10s and 10t had shown moderate activities against the gram-positive bacteria Staphylococcus aureus, Bacillus subtilis and against fungi Escherichia coli and Proteus vulgaris.

The crystal structure of 1-(N1-benzyl-2-methyl-4-nitro-imidazol-5-yl)-4-(prop-2-yn-1-yl) piperazine, C18H21N5O2

C18H21N5O2, monoclinic, P21/c (no. 4), a = 10.0914(6) Å, b = 11.8919(7) Å, c = 15.545(1) Å, β = 102.321(6)°, V = 1822.5(2) Å3, Z = 4, R gt (F) = 0.0503, wR ref (F 2) = 0.1419, T = 293(2) K.

Nitroimidazoles Part 9. Synthesis, molecular docking, and anticancer evaluations of piperazine-tagged imidazole derivatives

New piperazine-tagged imidazole derivatives were synthesized via reaction of 1-alkyl/aryl-5-bromo-2-alkyl-4-nitro-1H-imidazoles 1–3 with piperazine nucleophiles. Nine selected compounds were assessed for their antiproliferative inhibition potency against five human cancer cell lines (MCF-7, PC3, Du145, HepG2 and Dermal/Fibroblast). Compounds 7 and 10 are the most potent anticancer agents on HepG2 cell line with IC50 values of (5.6 ± 0.5 µm) and (29.6 ± 7.6 µm) respectively, and on MCF-7 with IC50 values of (32.1 ± 5.6 µm) and (46.2 ± 8.2 µm) respectively. The molecular docking of compounds 7 and 10 has been studied, and the results reveal that the newly designed piperazine-tagged imidazole derivatives bind to the hydrophobic pocket and polar contact with high affinity.

Antitumor Activity In Vitro Provided by N-Alkyl-Nitroimidazole Compounds

Background:

Cancer is one of the most common diseases in the world, with over 18 million new cases estimated in 2018. Many of the drugs used for cancer can have significant adverse effects and variable effectiveness. Nitroimidazoles are prodrugs that usually have shown antimicrobial activity specifically antiparasitic. However, its antitumor activity in vitro has barely been explored.

Objective:

The aim of this study is to determine the influence of the length of the substituted N-alkyl chain in the imidazole ring on the antitumor activity in vitro.

Methods:

Four nitroimidazoles were obtained by chemical synthesis varying the length of the substituted N-alkyl chain from methyl to butyl. The antitumor activity of N-alkyl-nitroimidazoles was evaluated by MTT assay employing two tumor cell lines (MDA-MB231 and A549).

Results:

In this study, it was reported that N-alkyl nitroimidazoles exhibited an LC50 as low as 16.7 µM in breast tumor cells MDA-MB231 while in normal Vero kidney cells, the LC50 was around 30 µM. It was also reported that the length of the substituted N-Alkyl chain in the imidazole ring affects the antitumoral activity in A549 lung cells.

Conclusion:

Increasing the length of the substituted N-Alkyl chain in the imidazole ring decreased the antitumor activity against only A549 cancer cells. N-alkyl nitroimidazoles exhibited considerable selectivity towards tumor cell lines.

Crystal structure of 3-(1-benzyl-2-ethyl-4-nitro-1H-imidazol-5-ylthio)-propanoic acid, C15H17N3O4S

C15H17N3O4S, monoclinic, P21/c (no. 14), a = 8.7938(5) Å, b = 10.3071(4) Å, c = 18.0413(7) Å, β = 79.704(5)°, V = 1608.91(13) Å3, Z = 4, R gt(F) = 0.0535, wR ref(F 2) = 0.1447, T = 293(2) K.

Nitroimidazoles Part 6. Synthesis, Structure and in Vitro anti-HIV Activity of New 5-substituted Piperazinyl-4-nitroimidazole Derivatives

2-Amino-1-[4-(1-benzyl-2-ethyl-4-nitro-1 H-imidazol-5-yl)piperazin-1-yl]ethanone [6] was prepared from 1-(1-benzyl-2-ethyl-4-nitro-1 H-imidazol-5-yl) piperazine [3]. A series of new 2-oxoethyl-arylamide [9,10] and 2-oxoethyl-arylsulphonamide [11–14] derivatives were synthesized from [6] with the aim of developing new non-nucleoside reverse transcriptase inhibitors. Alternatively, the amine [17] was synthesized from [3] via the phthalimide derivative [16]. The arylsulphonamide derivatives [18–23] and the arylamide analogues [24–26] were synthesized from [17]. The compounds were evaluated for their anti-HIV-1 and anti-HIV-2 activity in MT-4 cells.

Synthesis and in-vitro antibacterial activity of 5-substituted 1-methyl-4-nitro-1H-imidazoles

A series of 5-substituted 1-methyl-4-nitro-1H-imidazole derivatives were synthesized and evaluated for in-vitro antibacterial activity against a panel of microorganisms including Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis, Escherichia coli, Klebsiella pneumonia, Enterobacter aerogenes, and Helicobacter pylori using conventional agar dilution method. Among the test compounds, 1-methyl-4-nitro-5-(phenylsulfonyl)-1H-imidazole was the most potent against Gram-positive bacteria, with a MIC value of < or =8 microg/mL. All compounds showed no significant activity against Gram-negative bacteria at concentrations < or =64 microg/mL. The MIC values against 15 clinical isolates of H. pylori indicated that compounds 10 and 11 were the most active compounds in this series in terms of inhibiting the growth of H. pylori (MIC = 2 microg/mL). It was also demonstrated that their corresponding activities were four times larger than that of metronidazole.