Synthesis, antimicrobial and molecular docking studies of enantiomerically pure N-alkylated β-amino alcohols from phenylpropanolamines

Design, Synthesis, Molecular Docking, and In Vitro Antibacterial Evaluation of Benzotriazole-Based β-Amino Alcohols and Their Corresponding 1,3-Oxazolidines

In the present study, a series of benzotriazole-based β-amino alcohols were efficiently synthesized in excellent yields via aminolysis of benzotriazolated epoxides under catalyst- and solvent-free conditions. Further these β-amino alcohols were successfully utilized to synthesize the corresponding benzotriazole-based oxazolidine heterocyclic derivatives. All the synthesized compounds were characterized by various spectroscopic techniques such as 1H NMR, 13C NMR, and mass spectroscopy for structure elucidation. The compounds were subjected to a microtiter plate-based antimicrobial assay. The antimicrobial activity results reveal that the compounds 4a, 4e, and 5f were found to be active against Staphylococcus aureus (ATCC-25923) with minimum inhibitory concentrations (MICs) of 32, 8, and 64 μM, respectively. Also, the compounds 4a, 4e, 4k, 4i, 4m, 4n, 4o, 5d, 5e, 5f, 5g, and 5h showed effective activity against Bacillus subtilis (ATCC 6633) with MICs of 64, 16, 16, 16, 64, 16, 64, 64, 32, 64, 8, and 16 μM, respectively. A biological investigation was conducted, including molecular docking of two compounds with several receptors to identify and confirm the best ligand-protein interactions. Hence, this study found a significant strategy to diversify the chemical molecules. The synthesized compounds play a potential role as an antibacterial intensifier against some pathogenic bacteria for the development of antibacterial substances.

Dry-to-wet fluctuation of moisture contents enhanced the mineralization of chloramphenicol antibiotic

Due to livestock wastewater irrigation, soil is becoming one of the major sinks of antibiotics in the environment. Recently, it is getting recognized that a variety of minerals under low moisture conditions can induce strong catalytic hydrolysis to antibiotics. However, the relative importance and implication of soil water content (WC) for natural attenuation of soil residual antibiotics has not been well recognized. In order to explore the optimal moisture levels and the key soil properties dominating for the high catalytic hydrolysis activities of soils, this study collected 16 representative soil samples across China, and assessed their performances to degrade chloramphenicol (CAP) under different moisture levels. The results showed that the soils with low organic matter contents (< 20 g/kg) and high amounts of crystalline Fe/Al were particularly effective in catalyzing CAP hydrolysis when exposed to low WC (< 6%, wt/wt), leading to CAP hydrolysis half-lives of <40 d Higher WC greatly suppressed the catalytic activity of the soil. By utilizing this process, it is possible to integrate abiotic and biotic degradation to enhance the mineralization of CAP, attributing to that the hydrolytic products are more available for soil microorganisms. As expected, the soils experienced periodic dry-to-wet moisture conditions (i.e., the WC shifting from 1 to 5% to 20-35%, wt/wt) exhibited higher degradation and mineralization of ¹⁴C-CAP, in comparison with the constant wet treatment. Meanwhile, the bacterial community composition and the specific genera showed that the dry-to-wet fluctuation of soil WC relieved the antimicrobial stress to bacterial community. Our study verifies the critical role of soil WC in mediating the natural attenuation of antibiotics, and guides to remove antibiotics from both wastewater and soil.

A New Class of β-Pyrrolidino-1,2,3-Triazole Derivatives as β-Adrenergic Receptor Inhibitors: Synthesis, Pharmacological, and Docking Studies

New 1,4-disubstituted β-pyrrolidino-1,2,3-triazoles were synthesized using a reusable copper-iodide-doped neutral alumina catalyst. Synthesis of diversely substituted triazoles and recyclability of CuI catalyst explains the broad scope of this protocol. The synthesized compounds were screened for their antimicrobial and anticancer properties. Most of the compounds showed significant antimicrobial activities against all the tested microorganisms compared to standard drugs. Furthermore, compounds 5a, 5e, 5g, 5h, 5i, and 5j showed moderate to potent activities against A549 and HepG-2 cells. In addition, compounds 5g and 5h displayed potential cytotoxicity activity against A549 cells with IC₅₀ values of 72 ± 3.21 and 58 ± 2.31 µM, respectively. The molecular docking study revealed that some of the synthesized compounds exhibited comparable binding as co-crystalized ligands with the DNA topoisomerase IV and anaplastic lymphoma kinase receptors.

Synthesis and Cytotoxic Evaluation of Artemisinin Derivatives Containing an Aminopropanol Group

Series of novel artemisinin derivatives were designed and synthesized in which the amino propanol group was bonded to the artemisinin nucleus through C-C linkage. Ten new compounds were thus successfully prepared and evaluated as cytotoxic agents, revealing an interesting anticancer activity in KB and HepG2 cancer cell lines.

Broadband Microwave Spectroscopy of Prototypical Amino Alcohols and Polyamines: Competition between H-Bonded Cycles and Chains

The rotational spectra of the amino alcohols d-allo-threoninol, 2-amino-1,3-propanediol, and 1,3-diamino-2-propanol and the triamine analog, propane-1,2,3-triamine, have been investigated under jet-cooled conditions over the 7.5-18.5 GHz frequency range using chirped-pulsed Fourier transform microwave spectroscopy. Microwave transitions due to three conformers of d-allothreoninol, four conformers of 2-amino-1,3-propanediol, four conformers of 1,3-diamino-2-propanol, and four conformers of propane-1,2,3-triamine have been identified and assigned, aided by comparison of the fitted experimental rotational constants with the predictions for candidate structures based on an exhaustive conformational search using force field, ab initio and DFT methods. Distinctions between conformers with similar rotational constants were made on the basis of the observed nuclear quadrupole splittings and relative line strengths, which reflect the direction of the permanent dipole moment of the conformers. With three adjacent H-bonding substituents along the alkyl chain involving a combination of OH and NH2 groups, hydrogen-bonded cycles (3 H-bonds) and chains (2 H-bonds) remain close in energy, no matter what the OH/NH2 composition. Two families of H-bonded chains are possible, with H-bonding substituents forming curved chain or extended chain structures. Percent populations of the observed conformers were extracted from the relative intensities of their microwave spectra, which compare favorably with relative energies calculated at the B2PLYP-D3BJ/aug-cc-pVTZ level of theory. In glycerol (3 OH), d-allothreoninol (2 OH, 1 NH2), 2-amino-1,3-propanediol (2 OH, 1 NH2), and 1,3-diamino-2-propanol (1 OH, 2 NH2), H-bonded cycles are most highly populated, followed by curved chains (3 OH or 2 OH/1 NH2) or extended chains (1 OH/2 NH2). In propane-1,2,3-triamine (3 NH2), H-bonded cycles are pushed higher in energy than both curved and extended chains, which carry all the observed population. The NH2 group serves as a better H-bond acceptor than donor, as is evidenced by optimized structures in which H-bond lengths fall into the following order: r(OH···N) ≈ r(OH···O) < r(NH···N) ≈ r(NH···O).

Synthetic investigation on chirally pure Mannich derivatives of pseudophenylpropanolamine and their anticancer properties against HepG-2 cells with inhibition of JAK2/STAT3

In vitro and in vivo anticancer activity of compound 3a was proved as a novel blocker of JAK2/STAT3 signaling pathway and exerts both anti-proliferative and apoptotic activities in HepG-2 cells with xenograft mice model.

Synthesis of BF₃ catalyzed Mannich derivatives with excellent ee from phenylpropanolamine, study of their antimicrobial activity and molecular docking

Antimicrobial agents 4a-g and 5a-g with very good potency were synthesized with 100% ee from phenylpropanolamine (norephedrine) by BF3 catalyzed three components one pot Mannich reaction in good yields. Obtained compounds were characterized using spectral techniques. Antimicrobial study of these compounds revealed a good to very high potential activity against tested microbes when compared to standard antimicrobial drugs streptomycin and ketoconazole. These synthesized compounds exhibited significant minimum inhibitory concentration (MIC) values against Gram positive and Gram negative bacteria. Amongst compound 4b, 4c, 4d, 4e, 5a, and 5e exhibited very high potent MIC values against tested twelve bacteria and three fungi when compared to control. When subjected to molecular docking, in silico studies revealed significant binding energies ranging from -7.06 to -8.90 kcal/mol for all obtained compounds towards target receptor DNA topoisomerase IV and amongst compounds 4b and 4d have shown maximum binding energies 8.70 and 8.90 kcal/mol, respectively.