ansa-Zirconocenes Based on N-Substituted 2-Methylcyclopenta[b]Indoles: Synthesis and Catalyst Evaluation in Liquid Propylene Polymerization

Synthesis, Antimicrobial and Antibiofilm Activities, and Molecular Docking Investigations of 2-(1H-Indol-3-yl)-1H-benzo[d]imidazole Derivatives

The treatment of many bacterial and fungal infections remains a problem due to increasing antibiotic resistance and biofilm formation by pathogens. In the present article, a methodology for the chemoselective synthesis of 2-(1H-indol-3-yl)-1H-benzo[d]imidazole derivatives is presented. We report on the antimicrobial activity of synthesized 2-(1H-indol-3-yl)-1H-benzo[d]imidazoles with significant activity against Staphylococcus aureus ATCC 25923, Staphylococcus aureus ATCC 43300 (MRSA), Mycobacterium smegmatis (mc(2)155/ATCC 700084), and Candida albicans ATCC 10231. High activity against staphylococci was shown by indolylbenzo[d]imidazoles 3ao and 3aq (minimum inhibitory concentration (MIC) < 1 µg/mL) and 3aa and 3ad (MIC 3.9-7.8 µg/mL). A low MIC was demonstrated by 2-(1H-indol-3-yl)-1-methyl-1H-benzo[d]imidazole (3ag) against M. smegmatis and against C. albicans (3.9 µg/mL and 3.9 µg/mL, respectively). 2-(5-Bromo-1H-indol-3-yl)-6,7-dimethyl-1H-benzo[d]imidazole (3aq) showed a low MIC of 3.9 µg/mL against C. albicans. Compounds 3aa, 3ad, 3ao, and 3aq exhibited excellent antibiofilm activity, inhibiting biofilm formation and killing cells in mature biofilms. Molecular docking analysis identified three potential interaction models for the investigated compounds, implicating (p)ppGpp synthetases/hydrolases, FtsZ proteins, or pyruvate kinases in their antibacterial action mechanism.

The Synthesis and Biological Evaluation of 2-(1H-Indol-3-yl)quinazolin-4(3H)-One Derivatives

The treatment of many bacterial diseases remains a significant problem due to the increasing antibiotic resistance of their infectious agents. Among others, this is related to Staphylococcus aureus, especially methicillin-resistant S. aureus (MRSA) and Mycobacterium tuberculosis. In the present article, we report on antibacterial compounds with activity against both S. aureus and MRSA. A straightforward approach to 2-(1H-indol-3-yl)quinazolin-4(3H)-one and their analogues was developed. Their structural and functional relationships were also considered. The antimicrobial activity of the synthesized compounds against Mycobacterium tuberculosis H₃₇Rv, S. aureus ATCC 25923, MRSA ATCC 43300, Candida albicans ATCC 10231, and their role in the inhibition of the biofilm formation of S. aureus were reported. 2-(5-Iodo-1H-indol-3-yl)quinazolin-4(3H)-one (3k) showed a low minimum inhibitory concentration (MIC) of 0.98 μg/mL against MRSA. The synthesized compounds were assessed via molecular docking for their ability to bind long RSH (RelA/SpoT homolog) proteins using mycobacterial and streptococcal (p)ppGpp synthetase structures as models. The cytotoxic activity of some synthesized compounds was studied. Compounds 3c, f, g, k, r, and 3z displayed significant antiproliferative activities against all the cancer cell lines tested. Indolylquinazolinones 3b, 3e, and 3g showed a preferential suppression of the growth of rapidly dividing A549 cells compared to slower growing fibroblasts of non-tumor etiology.

The structural diversity of heterocycle-fused potassium cyclopentadienides

Cyclopentadienides of d- and f-elements are highly important complexes with undoubted potential for practical applications. Annelation of a heterocyclic fragment with an η5-ring results in substantial improvement of the catalytic properties of these compounds, called "heterocenes"; the investigation of metal coordination with these specific ligands is a highly important problem. We prepared potassium derivatives 5-8 of heterocycle-annelated cyclopentadienes with different structures - derivatives of cyclopenta[1,2-b:4,3-b']dithiophene (1), indeno[2,1-b]indole (2), indeno[1,2-b]indole (3), and indeno[1,2-b]indolizine (4) and studied the crystal and molecular structures of these salts by X-ray diffraction. We found that heterocycle-fused cyclopentadienides demonstrate remarkable diversity in metal-ligand coordination modes and crystal packing, with formation of two-dimensional polymeric (5), linear polymeric (6), tetrameric (7) and monomeric (8) structures. The NMR spectral data and results of DFT modeling indicate an increase in electron density in the cyclopentadienyl fragment, and this effect was found to be larger in the derivative of the new indolizine ligand precursor 4. The results of our study will be used in the design of next-generation catalysts of α-olefin polymerization.

Dichlorido[(1,2,3,3a,8b-η)-2,4-dimethylcyclopenta[b]indolyl)(η5-pentamethylcyclopentadienyl)zirconium(IV)

In the structure of the title compound, [Zn(C13H12N)(C10H15)Cl2], the dihedral angle between the planes of rings coordinating to Zr is 51.6 (2)°. The Cl—Zr—Cl angle is 97.52 (4)°. The crystal structure is stabilized by H...Cl and C—H...π interactions.