Facile synthesis of caerulomycin E by the formation of 2,2′-bipyridine core via a 2-pyridyl substituted 4H-pyran-4-one. Formal synthesis of caerulomycin A

A new approach to caerulomycins A and E via a 6-methyl-2-(2-pyridyl)-4H-pyran-4-one is described. The pyranone precursor is prepared by Claisen condensation of acetylacetone enol ether with ethyl picolinate.     

Synthesis of two novel cobalt complexes and their crystal structures

Two new cobalt complexes were successfully synthesized from the reaction of binaphthyl Schiff base 2 with Co(OAc)₂ in the presence of sodium methoxide at 80 °C for 24 h and Co(acac)₃ in toluene under reflux. Their unique crystal structures are unambiguously disclosed by X‐ray analysis. Complex 3 is triclinic, space group P1 , unit cell dimensions a = 10.742(2) Å, b = 11.153(2) Å, c = 12.715 Å, α = 79.865(3) °, β = 76.053 °, γ = 72.532(4) °, volume 1401.3(5) ų, Z = 2. Complex 4 is triclinic, space group P1 , unit cell dimensions a = 10.801(2) Å, b = 12.554(3) Å, c = 15.219(3) Å, α = 105.672(4) °, β = 103.048 °, γ = 104.594(4) °, volume 1824.8(7) ų, Z = 2, calculated density 1.428 Mg m⁻³. Copyright © 2003 John Wiley & Sons, Ltd.     

Comparison on photo-initiators for the preparation of methacrylate monolithic columns for capillary electrochromatography

The synthesis of lauryl methacrylate monoliths for capillary electrochromatography by UV polymerization using several free-radical initiators (α,α′-azobisisobutyronitrile, 2,2-dimethoxy-2-phenylacetophenone, dibenzoyl peroxide (BPO) and lauroyl peroxide (LPO)) has been investigated. Using a 1,4-butanediol/1-propanol mixture as porogenic solvent, the influence of each initiator and its content on the morphological and electrochromatographical properties of beds was evaluated. Under their respective optimum content, satisfactory separations of a test mixture of PAHs with similar efficiencies (minimum plate heights of 8.0–12.7 μm obtained from Van Deemter plots) were achieved for the four investigated photo-initiators. The columns photo-polymerized with LPO provided the best compromise between chromatographic performance and analysis time. Moreover, this initiator showed a fine control in the column retention properties. The resulting monolithic columns exhibited a good run-to-run repeatability in the tested chromatographic parameters (RSD < 2.4%) for all initiators investigated; and satisfactory column-to-column repeatability (RSD < 6.0%), except for beds photo-polymerized with BPO (RSD < 10.8%).     

2,2′-Biimidazole as an Efficient Ligand for Copper(I)-Catalyzed C‒N Coupling Reactions

An efficient copper(I)-catalyzed system using 2,2′-biimidazole as the ligand was applied to N-arylation of a broad spectrum of nitrogen nucleophiles with aryl halides. The reactions were carried out in relatively mild conditions with good to excellent yields.     

1H NMR assignment corrections and 1H, 13C, 15N NMR coordination shifts structural correlations in Fe(II), Ru(II) and Os(II) cationic complexes with 2,2′‐bipyridine and 1,10‐phenanthroline

¹H, ¹³C and ¹⁵N NMR studies of iron(II), ruthenium(II) and osmium(II) tris‐chelated cationic complexes with 2,2′‐bipyridine and 1,10‐phenanthroline of the general formula [M(LL)₃]²⁺ (M = Fe, Ru, Os; LL = bpy, phen) were performed. Inconsistent literature ¹H signal assignments were corrected. Significant shielding of nitrogen‐adjacent protons [H(6) in bpy, H(2) in phen] and metal‐bonded nitrogens was observed, being enhanced in the series Ru(II) → Os(II) → Fe(II) for ¹H, Fe(II) → Ru(II) → Os(II) for ¹⁵N and bpy → phen for both nuclei. The carbons are deshielded, the effect increasing in the order Ru(II) → Os(II) → Fe(II). Copyright © 2010 John Wiley & Sons, Ltd.     

A reusable CuSO4 · 5H2O/cationic 2,2′‐bipyridyl system catalyzed homocoupling of terminal alkynes in water

A reusable CuSO₄ · 5H₂O/cationic 2,2′‐bipyridyl system catalyzed the homocoupling reaction of terminal alkynes in water using I₂ as the additive in the presence or absence of tetrabutylammonium bromide, giving the 1,3‐diynes in good to high yields. After reaction, the residual aqueous solution could be reused several times. Copyright © 2011 John Wiley & Sons, Ltd.     

Anti-AIDS agents 83. Efficient microwave-assisted one-pot preparation of angular 2,2-dimethyl-2H-chromone containing compounds

A novel and efficient microwave-assisted one-pot reaction was developed to synthesize angular 2,2-dimethyl-2H-chromone-containing compounds, which is the first and key step in the synthesis of potent DCK and DCP anti-HIV agents. The newly developed microwave synthesis conditions dramatically shortened the reaction time from 2 days to 4 h with improved yields.     

Biological studies and computational modeling of two new copper complexes derived from β-diketones and their nano-complexes

Abstract

The present study was conducted to design and develop new complexes and their metal-based nanodrug (registered as Casiopeínas^® for cancer) with a low toxicity, high efficiency, and high selectivity. First, complexes ([Cu(TTA)(bpy)₂] (1) and [Cu(TTA)₂(en)] (2) (TTA = 4,4,4-trifluoro-1-(2-furyl)-1,3-butanedione) were synthesized and characterized by X-ray diffraction studies, CHN analysis, conductivity measurements, FT-IR and UV-vis spectroscopy. Second, nanoparticles (NPs) of 3 and 4 with the average size of 63.04 and 85.39?nm were prepared with ultrasound. Scanning electron microscopy patterns of 3 and 4 showed irregular spherical and nanorod particles with spongy surface. Furthermore, the anticancer properties of compounds and nano-compounds were studied in MKN-45 cell line. Then, apoptosis studies were carried out utilizing AO/EB staining methods. Finally, to confirm the in vitro experimental data, the theoretical study was carried out by molecular docking studies. The results of DNA docking analysis revealed that 1 and 2 were inserted with DNA via the minor groove. The binding affinity monitors the order of 1?>?2, with a preference of binding to A-T over G-C base pairs sequences.