New Multifunctional Agents for Potential Alzheimer's Disease Treatment Based on Tacrine Conjugates with 2-Arylhydrazinylidene-1,3-Diketones

Alzheimer's disease (AD) is considered a modern epidemic because of its increasing prevalence worldwide and serious medico-social consequences, including the economic burden of treatment and patient care. The development of new effective therapeutic agents for AD is one of the most urgent and challenging tasks. To address this need, we used an aminoalkylene linker to combine the well-known anticholinesterase drug tacrine with antioxidant 2-tolylhydrazinylidene-1,3-diketones to create 3 groups of hybrid compounds as new multifunctional agents with the potential for AD treatment. Lead compounds of the new conjugates effectively inhibited acetylcholinesterase (AChE, IC50 0.24-0.34 µM) and butyrylcholinesterase (BChE, IC50 0.036-0.0745 µM), with weak inhibition of off-target carboxylesterase. Anti-AChE activity increased with elongation of the alkylene spacer, in agreement with molecular docking, which showed compounds binding to both the catalytic active site and peripheral anionic site (PAS) of AChE, consistent with mixed type reversible inhibition. PAS binding along with effective propidium displacement suggest the potential of the hybrids to block AChE-induced β-amyloid aggregation, a disease-modifying effect. All of the conjugates demonstrated metal chelating ability for Cu2+, Fe2+, and Zn2+, as well as high antiradical activity in the ABTS test. Non-fluorinated hybrid compounds 6 and 7 also showed Fe3+ reducing activity in the FRAP test. Predicted ADMET and physicochemical properties of conjugates indicated good CNS bioavailability and safety parameters acceptable for potential lead compounds at the early stages of anti-AD drug development.

Copper-catalyzed [4 + 2] annulation reaction of β-enaminones and aryl diazonium salts without external oxidant: synthesis of highly functionalized 3H-1,2,4-triazines via homogeneous or heterogeneous strategy

Herein, both homogeneous and heterogeneous strategies were developed to access highly functionalized 3H-1,2,4-triazines using Cu-catalyzed [4 + 2] annulation.

(E)-7-[(4-Nitro-phen-yl)diazen-yl]-3a-(p-tol-yl)-2,3,3a,4-tetra-hydro-1H-benzo[d]pyrrolo-[1,2-a]imidazol-1-one 0.58-dimethyl sulfoxide 0.42-aceto-nitrile solvate: crystal structure, Hirshfeld analysis and DFT estimation of the energy of inter-molecular inter-actions

In the crystal structure of the title compound, C₂₃H₁₉N₅O₃·0.58C₂H₆OS·0.42C₂H₃N, prepared by the azo coupling of the 4-nitro­phenyl­diazo­nium salt with 3a-(p-tol­yl)-2,3,3a,4-tetra­hydro-1H-benzo[d]pyrrolo­[1,2-a]imidazol-1-one, the azo mol­ecules are linked by N—H⋯O hydrogen bonds into chains along the a-axis direction, and by the π–π inter­action into [101] chains.

In the crystal structure of the title compound, C₂₃H₁₉N₅O₃·0.58C₂H₆OS·0.42C₂H₃N, prepared by the azo coupling of the 4-nitro­phenyl­diazo­nium salt with 3a-(p-tol­yl)-2,3,3a,4-tetra­hydro-1H-benzo[d]pyrrolo­[1,2-a]imidazol-1-one, the azo mol­ecules are linked by N—H⋯O hydrogen bonds into chains along the a-axis direction, and by the π–π inter­action into [101] chains. The dimethyl sulfoxide and aceto­nitrile solvent mol­ecules occupy the same positions, with populations of 0.585 (3) and 0.415 (3), respectively. These mol­ecules take part in C—H⋯O(N) and C—H⋯π contacts. The energy of the π–π inter­actions was estimated using DFT calculations. The Hirshfeld mol­ecular surface analysis revealed the positions of the most important inter­molecular contacts, such as hydrogen bonds and π–π inter­actions.

Ammonium chloride catalyzed synthesis of novel Schiff bases from spiro[indoline-3,4'-pyran]-3'-carbonitriles and evaluation of their antimicrobial and anti-breast cancer activities

Background

Indolinone and spiro-indoline derivatives have been employed in the preparation of different important therapeutic compounds required for treatment of anticonvulsants, antibacterial, Antitubercular, and anticancer activities. Schiff bases have been found to possess various pharmacological activities such as antitubercular, plant growth inhibiting, insecticsidal, central nerve system depressant, antibacterial, anticancer, anti-inflammatory, and antimicrobial. Mannich bases have a variety of biological activities such as antibacterial and antifungal activities.

Results

In this study, a green, rapid and efficient protocol for the synthesis of a new series of Schiff bases from spiro[indoline-3,4′-pyran]-3′-carbonitrile derivatives using ammonium chloride as a very inexpensive and readily available reagent. The prepared compounds were assessed in vitro for their antimicrobial activity. Also, the cytotoxic activity of the prepared compounds was assessed in vitro against human cells line MCF7 breast cancer.

Conclusion

Good activity was distinguished for Schiff bases from spiro[indoline-3,4′-pyran]-3′-carbonitriles, with some members recorded higher antimicrobial and anti-breast cancer activities.Graphical abstract

On substituted pyrazole derivatives. II. (E)-1-(4-{[1-(4-Fluorophenyl)-3,5-dimethyl-1H-pyrazol-4-yl]diazenyl}phenyl)ethanone and (E)-1-(4-chlorophenyl)-3,5-dimethyl-4-[2-(2-nitrophenyl)diazenyl]-1H-pyrazole

The molecular structures of (E)-1-(4-{[1-(4-fluorophenyl)-3,5-dimethyl-1H-pyrazol-4-yl]diazenyl}phenyl)ethanone, C19H17FN4O, (III), and (E)-1-(4-chlorophenyl)-3,5-dimethyl-4-[2-(2-nitrophenyl)diazenyl]-1H-pyrazole, C17H14ClN5O2, (IV), prepared by reaction of the corresponding β-diketohydrazones with substituted arylhydrazines in acid media, are nonplanar, with the planes of the lateral phenyl rings forming dihedral angles with that of the central pyrazole ring varying from 2.71 (7) to 45.22 (7)°. The crystal structures are supported by C—H...O, C—H...π and π–π weak intermolecular interactions together with some unusual trifurcated C—Cl...Cl—C contacts, which are discussed in detail.

Switching around two axles: controlling the configuration and conformation of a hydrazone-based switch

A hydrazone-based rotary switch, having a quinolinyl stator and a pyridine ring as part of the rotor, can be induced using pH to undergo a four-step switching sequence. This process yields three stable isomers and a fourth "metastable" one that can all be addressed separately based on the sequence of acid and base added. The switching process proceeds via conformational and/or configurational changes, allowing the molecule to rotate around two different axles.