Synthesis of imidazo[4,5-<Emphasis Type="Italic">e</Emphasis>]benzo[1,2-<Emphasis Type="Italic">c</Emphasis>;3,4-<Emphasis Type="Italic">c</Emphasis>´]difuroxanes

A method for the synthesis of imidazo[4,5-e]benzo[1,2-c;3,4-c´]difuroxanes, potential nitric oxide donors, has been developed. The synthesized compounds were characterized by IR and NMR spectroscopy, high resolution mass spectrometry, and elemental analysis.     

Basicity of Highly Substituted β-Octaalkyl-<Emphasis Type="Italic">meso</Emphasis>-aryl- and -<Emphasis Type="Italic">meso</Emphasis>-thienyl Porphyrins

5-Phenyl-, 5,15-diphenyl-5,15-di(thiophen-2-yl)-, and 5,10,15,20-tetraphenyloctaalkyl-21H,23H-porphyrins in benzene–acetic acid mixtures are moderate bases (pK–0.27 to–2.48). There is no simple correlation between the basicity constants and any electronic or geometric structure parameter of their molecules due to the contributions of three factors to the basicity: distortion of the planar structure in highly substituted macrocycles and their protonated forms, positive charge delocalization over the conjugated bond system, and electronic effects of substituents.     

Synthesis of New Thieno[2,3-<Emphasis Type="Italic">b</Emphasis>:5,4-<Emphasis Type="Italic">c</Emphasis>′]dipyridines

Summary. We describe the formation of thieno[2,3-b:5,4-c]dipyridines from 5,6-dihydropyridine-2(1H)-thiones. The two-step reaction mechanism was revealed by isolation of an intermediate. The oxo and thioxo groups of the obtained tricyclic compounds were hydrogenated selectively. The structures of all new compounds were elucidated by NMR experiments.Received December 17, 2002; accepted December 20, 2002 Published online June 2, 2003     

<Emphasis Type="Italic">N</Emphasis>-arylsulfanyl-<Emphasis Type="Italic">N</Emphasis>-arylsulfonyl(acyl)-<Emphasis Type="Italic">N</Emphasis>′-phenylthiourea sodium salts

Reactions of N-arylsulfonyl(acyl)arenesulfenamide sodium salts with phenyl isothiocyanate afforded N-arylsulfanyl-N-arylsulfonyl(acyl)-N-phenylthioura sodium salts which were found to increase thermal stability of finely dispersed poly(vinyl chloride).Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 10, 2004, pp. 1532–1535.Original Russian Text Copyright © 2004 by Koval, Oleinik.     

Crystal structure of the molecular complex of 1,3,5-<Emphasis Type="Italic">tris</Emphasis>-<Emphasis Type="Italic">m</Emphasis>-chlorophenylisocyanurate with ε-caprolactone

The molecular complexes of 1,3,5-tris-m-chlorophenylisocyanurate and ε-caprolactone were synthesized by the reaction of the latter with 3-chlorophenylisocyanate in the presence of triethylamine. Single crystals were grown, and the molecular and crystal structures of the synthesized complexes were investigated.     

Production and Accumulation of 4-<Emphasis Type="Italic">O</Emphasis>-Methyl-α-<Emphasis Type="SmallCaps">d</Emphasis>-Glucuronosyl-Xylotriose by Growing Culture of Thermophilic <Emphasis Type="Italic">Anoxybacillus</Emphasis> sp. Strain JT-12

A thermophilic Anoxybacillus sp. strain JT-12, isolated from soil, produced acidic xylotriose, 4-O-methyl-α-d-glucuronosyl-xylotriose (MeGlcAX₃), as a main product from birchwood xylan and accumulated them in the culture under optimum conditions at pH 7.0 and 55 °C using 0.75% (w/v) birchwood xylan as a carbon source for 42–72 h. The acidic xylotriose was purified by ethanol precipitation and high-performance liquid chromatography using NH₂ Lichosher® 100 column. The results of electrospray ionization mass spectrometry, mass to charge ratio (m/z) 603.23, confirmed that the purified sample was acidic xylotriose that had benefits and applications in many fields.     

Synthesis and reactivity of 2-(2-furyl)-1,7-dimethyl-1<Emphasis Type="Italic">H</Emphasis>,7<Emphasis Type="Italic">H</Emphasis>-benzo[1,2-<Emphasis Type="Italic">d</Emphasis>: 3,4-<Emphasis Type="Italic">d</Emphasis>′]diimidazole

2-(2-Furyl)-1,7-dimethyl-1H,7H-benzo[1,2-d: 3,4-d′]diimidazole was synthesized by the Weidenhagen reaction followed by N-methylation. Electrophilic substitution reactions of the title compound (nitration, bromination, sulfonation, formylation, and acylation) involved both the furan ring and central benzene fragment.     

<Emphasis Type="Italic">N</Emphasis>′-tetrazolylmethoxyl derivatives of <Emphasis Type="Italic">N</Emphasis>-methyldiazene <Emphasis Type="Italic">N</Emphasis>-oxides

A preparation method was developed for previously unknown tetrazole derivatives containing in the 1, 2, and/or 5 positions of the tetrazole ring N-methyldiazene-N-oxide-N′-oxymethyl groups.     

Rhodium(I) pentasubstituted cationic complexes on the basis of 1,2-<Emphasis Type="Italic">O</Emphasis>-Alkylidene-3,5,6-<Emphasis Type="Italic">O</Emphasis>-phosphinetriyl-α-<Emphasis Type="SmallCaps">D</Emphasis>-glucofuranose

Reaction of 1,2-O-alkylidene--D-glucofuranose 3,5,6-phosphites with dicarbonylrhodium(I) acetylacetonate was studied. The structure of the reaction products is determined by the reagent ratio. At a 5:1 molar ratio, the step ligand-exchange process yields chiral complexes of the [RhL₅]⁺acac^– type. Dynamics of and anion exchange in these complexes are considered.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 9, 2004, pp. 1418–1421.Original Russian Text Copyright © 2004 by A. Koroteev, Teleshov, M. Koroteev, and Nifantev.This revised version was published online in April 2005 with a corrected cover date.     

1,3-Diamino-2-Hydroxypropane-<Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>′,<Emphasis Type="Italic">N</Emphasis>′-Tetraacetic Acid: Crystal and Molecular Structures

The synthesis, IR spectroscopic study, and X-ray diffraction analysis (CIF file CCDC no. 1574078) are carried out for 1,3-diamino-2-hydroxypropane-N,N,N′,N′-tetraacetic acid (I). The structural units of a crystal of compound I are (H_4.5HPdta)^0.5– anions, (H_5.5HPdta)^0.5+ cations, and molecules of water of crystallization joined by a branched network of hydrogen bonds: strong intermolecular O–H…O and intramolecular N–H…O bonds.     

Cyclization of the substituted <Emphasis Type="Italic">N</Emphasis>-(<Emphasis Type="Italic">Ortho</Emphasis>-cyclopropylphenyl)-<Emphasis Type="Italic">N′</Emphasis>-aryl ureas and thioureas in the gas phase and solution

Electron ionization (EI), chemical ionization (CI), tandem mass spectrometry, high-resolution measurements, and labeling studies as well as quantum chemical calculations were used to understand the behavior of the molecular radical cations (EI) and protonated molecules (CI) of substituted N-(ortho-cyclopropylphenyl)-N'-aryl ureas and N-(ortho-cyclopropylphenyl)-N'-aryl thioureas in a mass spectrometer. Fragmentation schemes and possible mechanisms of primary isomerization were proposed. According to the fragmentation pattern, formation of the corresponding benzoxazines and benzothiazines was considered as the major process of isomerization of the original M(+.) and MH(+), although some portions of these ions definitely transformed into other structures. The treatment of N-(ortho-cyclopropylphenyl)-N'-phenyl urea and N-(ortho-cyclopropylphenyl)-N'-phenylthiourea in solution with strong acids formed predicted 4-ethyl-N-phenyl-4H-3,1-benzoxazin-2-amin and 4-ethyl-N-phenyl-4H-3,1-benzothiazin-2-amine as principal products.     

Synthesis of lupane and 19<Emphasis Type="Italic">β</Emphasis>,28-epoxy-18<Emphasis Type="Italic">α</Emphasis>-oleanane 2,3-<Emphasis Type="Italic">seco</Emphasis>-derivatives based on betulin

The α-hydroxyoximes of methyl betulonate and allobetulone were synthesized. Beckmann fragmentation of them produced the lupane and 19β,28-epoxy-18α-oleanane 2,3-seco-derivatives. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 491–494, September-October, 2008. Original article submitted July 4, 2008.     

Determination of the <Emphasis Type="Italic">R</Emphasis> ⇄ <Emphasis Type="Italic">S</Emphasis> enantiomerization barrier in 5,6-dihydrobenzoimidazo[1,2-<Emphasis Type="Italic">c</Emphasis>]quinazolines

Chiral imidazoquinazolines undergoing thermally induced reversible R ⇄ S enantiomerization have been synthesized by the interaction of 2-(o-aminophenyl)benzimidazoles with aldehydes and ketones. The benzimidazole fragment has been used for the first time as an indicator group in temperature-dependent ¹H NMR spectra for determining the energy barrier of this rearrangement. The effects of nearby substituents on the kinetic and activation parameters, and on the recyclization mechanism have been investigated.     

Complex formation of magnesium and calcium ions with trimethylenediamine-<Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>’,<Emphasis Type="Italic">N</Emphasis>’-tetraacetic acid

Stability constants and heat effects of the formation reactions of magnesium and calcium trimethylenediaminetetraacetates at 298.15 K and ionic strength of 0.1, 0.5, and 1.0 (mol/L KNO₃) have been determined by means of potentiometry and calorimetry. Standard thermodynamic parameters (log K⁰, Δ_rG⁰, Δ_rH⁰, and Δ_rS⁰) of the studied equilibriums have been determined.     

Synthesis and antibacterial and antifungal activities of <Emphasis Type="Italic">N</Emphasis>-(tetra-<Emphasis Type="Italic">O</Emphasis>-acetyl-β-<Emphasis Type="SmallCaps">d</Emphasis>-glucopyranosyl)thiosemicarbazones of substituted 4-formylsydnones

Background

Sydnone is a heterocycle that exhibits remarkable pharmacological activities, including antimicrobial, anti-inflammatory, analgesic, antipyretic and antioxidant activities. Thiosemicarbazones are of compounds that contain the –NHCSNHN=C< linkage group and are considerable interest because they exhibit important chemical properties and potentially beneficial biological activities. Similarly, thiosemicarbazones having carbohydrate moieties also exhibit various significant biological activities.

Results

The compounds of 3-formyl-4-phenylsydnones were obtained by Vilsmeyer-Haack’s formylation reaction and were transformed into thiosemicarbazones by condensation reaction with N-(2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl)thiosemicarbazide. Reaction were performed in the presence glacial acetic acid as catalyst using microwave-assisted heating method. Reaction yields were 43?85 %. The antimicrobial activities of these thiosemicarbazones were screened in vitro by using agar well diffusion and MIC methods. Among these thiosemicarbazones, compounds 4k, 4l, 4m and 4n were more active against all tested bacterial strains, especially against S. epidermidis, B. subtilis and E. coli. The MIC values in these cases are 0.156, 0.156 and 0.313 μg/mL, respectively. All compounds showed weak to moderate antifungal activity against C. albicans and A. niger than nystatin (MIC = 0.156?0.625 μg/mL vs. MIC = 0.078 μg/mL of nystatin), and thiosemicarbazones 4l, 4m and 4n exhibited significant activity with MIC = 0.156 μg/mL. These compounds also had good antifungal activity against F. oxysporum similarly to nystatin (MIC = 0.156 μg/mL). Among the tested compounds having halogen group 4k, 4l, 4m and 4n showed highest activity against three strains of fungal organisms.

Conclusions

In summary, we have developed a clean and efficient methodology for the synthesis of novel thiosemicarbazone derivatives bearing sydnone ring and d-glucose moiety; the heterocyclic and monosaccharide system being connected via ?NH?C(=S)NH?N=C< linker using molecular modification approach. The methodology could be further extended and used for the synthesis of other thiosemicarbazones of biological importance. 4-Formyl-3-arylsydnone N-(2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl)thiosemicarbazones have been synthesized under microwave-assisted heating conditions. Almost all obtained compounds showed remarkable activities against the tested microorganisms. Among the tested compounds having halogen group 4k, 4l, 4m and 4n showed highest activity against all tested strains of bacterial and fungal organisms.

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Graphical abstract:Synthesis and antibacterial and antifungal activities of N-(tetra-O-acetyl-β-D-glucopyranosyl)thiosemicarbazones of substituted 4-formylsydnones

     

Properties of a poly(ethylene glycol)-<Emphasis Type="Italic">block</Emphasis>-poly(<Emphasis Type="Italic">γ</Emphasis>-benzyl <Emphasis Type="SmallCaps">l</Emphasis>-glutamate)-<Emphasis Type="Italic">graft</Emphasis>-poly(ethylene glycol) copolymer membrane

Poly(ethylene glycol)-block-poly(γ-benzyl l-glutamate)-graft-poly(ethylene glycol) (PEG-block-PBLG-graft-PEG) copolymer was synthesized by the ester exchange reaction of PBLG-block-PEG copolymer with a PEG chain. Surface morphology of the PEG-block-PBLG-graft-PEG copolymer membrane was characterized by atomic force microscopy (AFM). Mechanical and chemical properties of the PEG-block-PBLG-graft-PEG copolymer membrane were investigated by tensile testing and contact angle testing. The effects of grafting ratio on the properties of PEG-block-PBLG-graft-PEG copolymer membrane were primarilly studied.     

SBR composites reinforced with <Emphasis Type="Italic">N</Emphasis>-isopropyl-<Emphasis Type="Italic">N</Emphasis>′-phenyl-<Emphasis Type="Italic">P</Emphasis>-phenylenediamine-modified clay

SBR compounds including the N-isopropyl-N’-phenyl-p-phenylenediamine-modified clay(organoclay) were prepared.Effects of modified clay and antioxidant(IPPD) contents on mechanical and rheological properties of SBR composites were studied.FTIR results confirmed that the clay was chemically modified by IPPD and changed into an organoclay.X-ray diffraction(XRD) results confirmed the increase in interlayer distance of the clay due to the insertion of IPPD.Rheological and cure characteristics of SBR compounds were determined using RPA(Rubber Process Analyzer) and rheometer.Scorch time and cure time of SBR compounds decreased with introduction of the organoclay.Mechanical properties and heat aging resistance of the SBR composites were improved significantly by incorporation of the organoclay.     

Directed Aminomethylation of Pyrrole,Indole, and Carbazole with <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N′</Emphasis>,<Emphasis Type="Italic">N′</Emphasis>-Tetramethylmethanediamine

Catalytic aminomethylation of pyrrole and indole with N,N,N′,N′-tetramethylmethanediamine in the presence of 5 mol % of ZrOCl₂·8H₂O proceeds selectively at the positions 2, 5 of pyrrole and 1, 3 of indole. Carbazole under the same conditions affords 3-formyl-9-aminomethyl derivative. The reaction in the presence of 5 mol % of K₂CO₃ occurs as monoaminomethylation: for pyrrole at the position 2, for indole at the position 3, and for carbazole at the nitrogen atom of the substrate. Water-soluble 1,1′-(1H-pyrrole-2,5-diyl)bis(N,N-dimethylmethanamine) exhibits a fungistatic activity with respect to phytopathogenic fungi Rhizoctonia solani.     

Physicochemical properties and complexing ability of <Emphasis Type="Italic">N</Emphasis>-(2-ethylhexanoyl)-<Emphasis Type="Italic">N</Emphasis>′-sulfonylhydrazines

The effect of substituent at the sulfonyl group on the physicochemical properties and complexing ability of the sulfonyl derivatives of 2-ethylhexanoic acid hydrazide of the general formula C₄H₉CH(C₂H₅)C(O)·NHNHSO₂C₆H₅R [R = H, CH₃, NO₂, NHC(O)CH₃, Cl] with respect to Cu(II), Co(II), and Ni(II) ions was studied.