Microwave-assisted synthesis of (3,5-disubstituted isoxazole)-linked benzimidazolone derivatives: DFT calculations and biological activities

Discovery of Tetrazolamide-benzimidazol-2-ones as Novel 4-Hydroxyphenylpyruvate Dioxygenase Inhibitors

4-Hydroxyphenylpyruvate dioxygenase (HPPD, EC 1.13.11.27) is one of the most valuable herbicide targets due to its unique biological functions. In search of HPPD inhibitors with promising biological performance, we designed and synthesized a series of novel tetrazolamide-benzimidazol-2-ones using a structure-based drug design strategy. Among the synthesized compounds, 1-(2-chlorobenzyl)-3-methyl-N-(1-methyl-1H-tetrazol-5-yl)-2-oxo-2,3-dihydro-1H-benzo[d]imidazole-4-carboxamide, 25, IC50 = 10 nM, was identified to be the most outstanding HPPD inhibitor, which showed more than 36-fold increased Arabidopsis thaliana HPPD (AtHPPD) inhibition potency than mesotrione (IC50 = 363 nM). Our AtHPPD-25 complex indicated that one nitrogen atom on the tetrazole ring and the oxygen atom on the amide group formed a classical bidentate chelation interaction with the metal ion, the benzimidazol-2-one ring created a tight π-π stacking interaction with Phe381 and Phe424, and some hydrophobic interactions were also found between the ortho-Cl-benzyl group and surrounding residues. Compound 32 showed more than 80% inhibition against all four tested weeds at 150 g ai/ha by the postemergence application. Our results indicated that the tetrazolamide-benzimidazol-2-one scaffold may be a new lead structure for herbicide discovery.

Synthesis, structure and Hirshfeld surface analysis of 1,3-bis-[(1-octyl-1H-1,2,3-triazol-4-yl)meth-yl]-1H-benzo[d]imidazol-2(3H)-one

The title mol-ecule, C29H44N8O, adopts a conformation resembling a two-bladed fan with the octyl chains largely in fully extended conformations. In the crystal, C-H⋯O hydrogen bonds form chains of mol-ecules extending along the b-axis direction, which are linked by weak C-H⋯N hydrogen bonds and C-H⋯π inter-actions to generate a three-dimensional network. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (68.3%), H⋯N/N⋯H (15.7%) and H⋯C/C⋯H (10.4%) inter-actions.

Design, synthesis, in silico, and in vitro evaluation of benzylbenzimidazolone derivatives as potential drugs on α-glucosidase and glucokinase as pharmacological targets

Benzimidazolones have shown biological activities, including antihyperglycemic and hypoglycemic, by inhibiting or activating of α-glu and GK. The aim of this study is the rational design of compounds using in silico assays to delimitate the selection of structures to synthesize and the in vitro evaluation of benzimidazolone derivatives in blood glucose control. A docking of 23 benzimidazolone derivatives was performed; selecting the compounds with better in silico profiles to synthesize by microwave-irradiation/conventional heat and evaluate in enzymatic in vitro evaluation. Compounds 2k, 2m, 2r, and 2s presented the best in silico profiles, showing good affinity energy (-10.9 to -8.6 kcal mol^-1) and binding with catalytic-amino acids. They were synthesized at 70 °C and 24 h using DMF as the solvent and potassium carbonate (yield: 22-38%). The results with α-glu showed moderate inhibition of 2k (14 ± 1.23-29 ± 0.45), 2m (12 ± 2.21-36 ± 0.30), 2r (7 ± 2.21-13 ± 1.34), and 2s (11 ± 0.74-35 ± 2.95) at evaluated concentrations (0.1 to 100 μg mL^-1). The GK activation assay showed an enzymatic activity increase; compound 2k increased 1.31 and 2.83 more than normal activity, 2m (2.13-fold), 2s (2.86 and 3.74-fold) at 100 and 200 μg mL^-1 respectively. The present study showed that the 2s derivative presents moderate potential as an α-glu inhibitor and a good activator potential of GK, suggesting that this compound is a good candidate for blood glucose control through antihyperglycemic and hypoglycemic mechanisms.

Copper Catalyzed Synthesis of Heterocyclic Molecules via C-N and C-O Bond Formation under Microwaves: A Mini-Review

Heterocyclic moieties play a significant role in the field of drug discovery. C-N and C-O bond formation reactions are the primary synthetic sequence for the generation of heterocyclic molecules. The generation of C-N and C-O bonds involves the use of mostly Pd or Cu catalysts although other transition metal catalyst's are also involved. However, in C-N and C-O bond formation reactions, several problems were faced such as catalytic systems containing costly ligands, lack of substrate scope, lots of waste generation, and high temperature conditions. So it is imperative to uncover new eco-friendly synthetic strategies. In view of enormous drawbacks, it is important to develop an alternate microwave-assisted synthesis of heterocycles via C-N and C-O bond formation, which provides a short reaction time, tolerance for functional groups, and less waste production. Numerous chemical reactions have been accelerated using microwave irradiation which provides a cleaner reaction profile, lower energy consumption, and higher yields. This review article highlights a comprehensive overview on the potential application of microwave assisted synthetic routes for the synthesis of diverse heterocycles via mechanistic pathways covering the year ranges from 2014 to 2023, along with possible biological interests.