Novel Polyhydroquinoline-Hydrazide-Linked Schiff’s Base Derivatives: Multistep Synthesis, Antimicrobial, and Calcium-Channel-Blocking Activities

Abstract

Polyhydroquinoline (PHQ) are the unsymmetrical Hantzsch derivatives of 1,4-dihydropyridines with several biological applications. In this work, twenty-five (3–27) new Schiff’s base derivatives of polyhydroquinoline hydrazide were synthesized in excellent to good yields by a multi-component reaction. The structures of the synthesized products (1–27) were deduced with the help of spectroscopic techniques, such as 1H-, 13C -NMR, and HR-ESI-MS. The synthesized products (1–27) were tested for their antibacterial and in vitro calcium -channel-blocking (CCB) potentials using the agar-well diffusion method, and isolated rat aortic ring preparations, respectively. Among the series, sixteen compounds were found to inhibit the growth of Escherichia coli and Enterococcus faecalis. Among them, compound 17 was observed to be the most potent one at a dose 2 µg/mL, with an 18 mm zone of inhibition against both bacteria when it was compared with the standard drug amoxicillin. Eight compounds showed CCB activity of variable potency; in particular, compound 27 was more potent, with an EC50 value of 0.7 (0.3–1.1) µg/mL, indicating their CCB effect.

“Synergistic Innovation: Crafting Indazole Derivatives for Advanced Anticancer, Antioxidant, and Antimicrobial Efficacy through Integrative Design and Holistic Evaluation”

“…This diazonium ion then undergoes coupling to form 5nitro-1H-indazole. [57] Step 2: Synthesis of 1-(2-Chloropyrimidin-4-yl)-5-nitro-1Hindazole (3).…”

“…The indazole nucleus, distinguished by its five-membered heterocyclic structure, has become a focal point of interest owing to its remarkable spectrum of pharmacological activities, spanning anticancer, antioxidant and antimicrobial properties. [2,3] The allure of indazole lies in its capacity to open up new vistas in therapy, presenting the tantalizing prospect of pioneering medications that have the potential to revolutionize the healthcare landscape. Its ubiquitous presence in nature establishes indazole as a pivotal scaffold for numerous indispensable molecules in the realms of biology and medicine.…”

“…Among the myriad of compounds under scrutiny, indazole derivatives have emerged as a particularly compelling class, captivating substantial attention for their auspicious pharmacological applications. The indazole nucleus, distinguished by its five‐membered heterocyclic structure, has become a focal point of interest owing to its remarkable spectrum of pharmacological activities, spanning anticancer, antioxidant and antimicrobial properties [2,3] . The allure of indazole lies in its capacity to open up new vistas in therapy, presenting the tantalizing prospect of pioneering medications that have the potential to revolutionize the healthcare landscape.…”

Antioxidant Activity, Molecular Docking and Quantum Studies of New Bis‐Schiff Bases Based on Benzyl Phenyl Ketone Moiety

“…[26,27] Depending on the kind of the attached substituents (R), azines can be either symmetric (R 1 R 2 = R 3 R 4 ) or asymmetric (R 1 R 2 ¼ 6 R 3 R 4 ). [28,29] The biological potentials of bis-Schiff bases, such as their anti-oxidant, anti-tumor, anti-bacterial, anti-proliferative, anticonvulsant, calcium channel blockers, urease, α-glucosidase inhibition and anti-parasitic properties have drawn more attention than those of other compounds. [30][31][32][33][34][35] Rahim with his collegues evaluated the α-glucosidase inhibition activity of bis-Schiff bases derived from benzimidazole nuclues in synthetic chemistry.…”

“…The organic compounds known as bis ‐Schiff bases or azines have the general formula (R 1 HC=N−N=CHR 2 ) and include two carbon nitrogen double bonds in their structures [26,27] . Depending on the kind of the attached substituents (R), azines can be either symmetric (R 1 R 2 =R 3 R 4 ) or asymmetric (R 1 R 2 ≠R 3 R 4 ) [28,29] …”