A Multifunctional Subphthalocyanine Nanosphere for Targeting,Labeling, and Killing of Antibiotic‐Resistant Bacteria

Developing a material that can combat antibiotic‐resistant bacteria, a major global health threat, is an urgent requirement. To tackle this challenge, we synthesized a multifunctional subphthalocyanine (SubPc) polymer nanosphere that has the ability to target, label, and photoinactivate antibiotic‐resistant bacteria in a single treatment with more than 99 % efficiency, even with a dose as low as 4.2 J cm⁻² and a loading concentration of 10 nM . The positively charged nanosphere shell composed of covalently linked SubPc units can increase the local concentration of photosensitizers at therapeutic sites. The nanosphere shows superior performance compared to corresponding monomers presumably because of their enhanced water dispersibility, higher efficiency of singlet‐oxygen generation, and phototoxicity. In addition, this material is useful in fluorescence labeling of living cells and shows promise in photoacoustic imaging of bacteria in vivo.     

New substituted 2-aminomethyl-2-oxo-2λ5-perhydro-[1,3,2]oxazaphospholo [3,4-a]pyridine: Design,synthesis and antimicrobial activity

The synthesis of a new series of P-heterocyclic compounds, substituted 2-aminomethyl-2-oxo-2λ⁵-perhydro-[1,3,2]oxazaphospholo[3,4-a]pyridine derivatives 8(a-j), was accomplished. A key intermediate, 2-(chloromethyl)-2-oxo-2λ⁵-perhydro-[1,3,2]oxazaphospholo[3,4-a]pyridine (6) was primarily synthesized by the condensation of (±)-2-piperidinemethanol (4) and chloromethylphosphonic dichloride (5); subsequently, it was treated with various heterocyclic amines/benzylamines/aminoacid esters, 7(a-j) to obtain the desired products. The structures of the newly synthesized compounds were elucidated by ¹H, ¹³C, and ³¹P NMR spectroscopy, mass spectra and elemental analyses. The biological potency of title products was investigated by screening in vitro antimicrobial activity. The bio-screening data revealed that most of the synthesized derivatives showed potent growth of inhibition against fungi while compared with bacteria. Particularly, compounds 8c and 8i against bacterial strains, and 8a and 8f against fungi exhibited promising activity.     

Physicochemical studies on bioactive Cr(III) coordination compounds with esters of hydrazine carboxylic acid as hetero donor ligands

Reaction between hydrazine derivative ligands (HrzE) or (HrzB) and chromium salt in 1:2 (metal:ligand) molar ratio yielded monometallic trivalent coordination compounds with general formula [Cr(HrzE)₂X₂]X and [Cr(HrzB)₂X₂]X, where (HrzE) = hydrazine carboxylic acid ethyl ester, (HrzB) = hydrazine carboxylic acid tert-butyl ester, and X = Cl^?, Br^? or F^?. Elemental analysis, conductivity measurements, magnetic moment measurements, and various spectroscopic techniques, viz. infrared, ultraviolet–visible, and electrospray ionization mass spectrometry, were applied to illustrate the structure and composition of the coordination compounds. Analytic and conductivity results were consistent with 1:1 electrolytic behavior and the proposed formulas of the coordination compounds. Electronic absorption data and magnetic moment parameters indicated octahedral geometry surrounding the metal ion in the coordination compounds. The in vitro antimicrobial behavior of the ligands and coordination compounds was screened using four bacterial strains (Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Salmonella typhi) and two fungal strains (Candida parapsilosis and Saccharomyces cerevisiae). The results indicated improved activity of the coordination compounds compared with the free ligands against the studied bacteria and fungi.     

A Facile Diversity‐Oriented Multicomponent One‐Pot Synthesis of 3‐Amino‐6,7‐dihydrobenzo[c]thiophen‐4(5H)‐one Derivatives from α‐Oxo‐N,S‐ketene Acetal

A convenient one‐pot multicomponent method for the preparation of 3‐amino‐6,7‐dihydrobenzo[c]thiophen‐4(5H)‐one derivative has been developed. Reaction of 1,3‐cyclohexanedione and phenyl isothiocynate gave α‐oxo‐N,S‐ketene acetal that were reacted in situ with 2‐chloromethylquniazoline‐4‐one derivatives, in the presence of sodium hydride to afford the target compound in reasonable overall yields.     

Synthesis and characterization of binuclear μ-oxo and μ-telluro molybdenum(V) complexes, [CpMo(O)(μ-Te)]2

Pyrolysis of an in-situ generated intermediate, produced in the reaction of [Cp^∗MoCl₄], 1, (Cp^∗ = η⁵-C₅Me₅) with [LiBH₄·THF], with an excess of difuryl ditelluride in toluene at 90 °C yielded syn and anti isomers of [Cp^∗Mo(O)(μ-Te)]₂ (2, 3) and [Cp^∗₂Mo₂O₂(μ-O)(μ-Te)] (4, 5). In a similar fashion, dibenzyl diselenide yielded syn and anti isomers of [Cp^∗Mo(O)(μ-Se)]₂ (6, 7), along with the known nido-[(Cp^∗Mo)₂B₄H₈Se₂]. Note that in parallel with 2-7, [(Cp^∗Mo)₂B₅H₉] was isolated as the major product in both cases. Compounds 2-7 have been isolated in modest yield as orange to brown crystalline solids. All the new compounds have been characterized in solution by mass, IR, ¹H, ¹³C, ⁷⁷Se and ¹²⁵Te NMR spectroscopy, and the structural types were unequivocally established by crystallographic analysis of 2-4 and 7.     

Stable aluminium fluoride chelates with triazacyclononane derivatives proved by X-ray crystallography and 18F-labeling study

A single crystal structure of an aluminium-fluoride complex of a model compound (NODA-benzyl) was studied to understand the co-ordination chemistry. Series of ligands with an extra carboxylic acid linker for biomolecule conjugation were studied for improved (18)F-labeling applications.     

Comparison of Eucalyptus cinerea essential oils produced by hydrodistillation and supercritical carbon dioxide extraction

The essential oil of Eucalyptus cinerea is reported to possess a higher 1,8-cineole content than other Eucalyptus species. Variations in the quantitative and qualitative characteristics of E. cinerea oil produced by hydrodistillation (HD) and supercritical carbon dioxide extraction (SCE) techniques and a comparison between glycoside-bound and free volatile constituents produced by HD have been studied. It was found that HD produced higher oil (free volatiles) content (3.1%) as compared with SCE (1.1%), whereas bound volatiles constituted only about 0.4%. Gas chromatographic (GC) analysis of the oil samples revealed significant difference in their chemical composition. The essential oil (free volatiles) produced by HD contained 1,8-cineole (85.1%) as the major constituent, followed by a-terpineol (7.2%) and limonene (4.4%). In the bound volatile fraction produced by HD, 1,8 cineole (20.6%), alpha-terpineol (7.6%), p-cymene (6.3%), and limonene (4.5%) were found as major constituents. The extract produced by SCE was dominated by 1,8-cineole (70.4%), a-terpineol (8.6%), globulol (3.1%), aromadendrene (2%), citronellal (1.7%), viridiflorol (1.3%), phytol (1.1%) and terpinen-4-ol (1%). Although HD produced higher oil yields, SCE produced better extract in terms of the number of components detected.     

Regioselective synthesis of 2,4,6-triaminopyridines

A regioselective synthesis of 2,4,6-trisubstituted pyridine is described starting from 2,6-dibromo-4-nitropyridine. All three different regioisomers of the 2,4,6-triamino substituted pyridine have been synthesized in four to five steps. The method described is a general route to unsymmetrical 2,4,6-trisubstituted amino pyridines.