Synthesis of α,β-disubstituted ferrocenes via a ferrocenylepoxide intermediate. Preparation and catalytic activity of a new chiral ferrocenyloxazoline

A short synthesis of the chiral oxazoline 10 (>95% e.e.) in six steps from chloroacetylferrocene is described. The ligand can be used successfully in an asymmetric Pd(0)-catalyzed allylic alkylation reaction.     

Iodine-poly(2-vinylpyridine-co-styrene-co-divinylbenzene) charge transfer complexes with antibacterial activity

In this work, we have developed three different copolymers based on 2-vinylpyridine, styrene and crosslinked with divinylbenzene (10-30 mol%). The copolymers were morphologically and chemically characterized by apparent density, swelling degree, elemental analysis, Fourier transform infrared spectrophotometry and optical microscopy. The formation of iodine complexes with these copolymers was carried out by two different procedures: with solvent, or not. The influence of the copolymers structure on the capacity of anchoring iodine has been investigated. The antibacterial properties of polymeric charge transfer complexes were determined towards 10³-10⁷ cells/mL dilutions from the auxotrophic AB1157 Escherichia coli strain.     

Synthesis of new fluorinated 1,5-benzoxazepine derivatives

A simple approach to the fluorinated 1,5-benzoxazepine ring system is described. By reacting commercially accessible aminophenols 1 and the trifluoroacetylvinyl ether 2, high yields of enaminones 3 were obtained. Functionalization of methyl group of compounds 3 gave rise to dieneamines 4 that were cyclized in acidic environment to benzoxazepine derivatives 5.     

High-throughput chemistry toward complex carbohydrates and carbohydrate-like compounds

In the area of peptide and nucleic acid chemistry and biology, high-throughput synthesis has played an important role in providing useful small-molecule-based chemical probes in understanding the structure and function relationships. The past several years, there has been a constant rise in interest toward understanding the biological roles and functions of another important class of biomolecules, i.e., carbohydrates and carbohydrate conjugates. Although at early stages, in recent years, several groups have developed high-throughput synthetic methods to obtain complex carbohydrates or carbohydrate-like small-molecules. The present review article summarizes some of these developments.     

The determination of chlorinated biphenyls,chlorinated dibenzodioxins,and chlorinated dibenzofurans by GC-MS

High resolution gas chromatography, with mass selective detection, has been used for the analysis of PCB on methyl 50 % octyl polysiloxane (SB 50 Octyl), methyl octadecyl polysiloxane, and a smectic polysiloxane (SB Smectic); and for the analysis of polychlorodibenzodioxins and polychlorodibenzofurans with 1 to 8 chlorine substituents on 100 % cyanopropyl siloxane (SP 2331), smectic polysiloxane (SB Smectic), a new polar stationary phase (DB-Dioxin). The analysis has also been performed by column coupling.     

Nitrogen extrusion from pyrazoline-substituted porphyrins and chlorins using long wavelength visible light

Protoporphyrin reacts with diazomethane to give pyrazolines which at long wavelength (approximately 630 nm) extrude nitrogen to give the corresponding cyclopropyl derivatives.     

Rb7[SiO4][VO4]: ein Ortho‐Silicat‐Vanadat(V)

Rb₇[SiO₄][VO₄]: an Ortho‐Silicate‐Vanadate(V) Rb₇[SiO₄][VO₄] has been obtained from a redox reaction between CdO and vanadium metal in the presence of Rb₂O and SiO₂ at 600 °C in an Ag container as yellow‐greenish transparent single crystals. The crystal structure determination (IPDS data: P2₁/c, a = 637.6(1) pm, b = 1039.7(1) pm, c = 2076.8(4) pm, β = 93.21(2)°, Z = 4, wR2 = 0.1319) reveals the presence of isolated complex anions, [SiO₄]^4— and [VO₄]^3—.     

Development and validation of a hydrophilic interaction liquid chromatography-tandem mass spectrometric method for the analysis of paroxetine in human plasma

A sensitive, simple, fast and rugged hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) method for the determination of paroxetine was developed and validated over curve range 0.050-50 ng/mL using only 0.4 mL plasma. This is the first published LC-MS/MS method and the low limit of quantitation of this method is 10-fold lower than previously published methods. A simple liquid-liquid extraction method using methyl-tert butyl ether (MTBE) as the extraction solvent was used to extract paroxetine and the internal standard (IS) fentanyl-d(5) from plasma. The extract was evaporated to dryness, reconstituted and injected onto a silica column using a low aqueous-high organic mobile phase. The chromatographic run time was 2.0 min per injection, with retention times of 1.1 and 1.2 min for paroxetine and IS, respectively. The detection was by monitoring paroxetine at m/z 330 --> 192 and IS at m/z 342 --> 188, respectively. The inter-day precision and accuracy of the quality control (QC) samples were <5.0% relative standard deviation (RSD) and <2.9% relative error (RE). This method can be used for supporting therapeutical drug monitoring and pharmacokinetic or drug-drug interaction studies.     

Coordination of 2,2'-bipyridyl and 1,10-phenanthroline to yttrium and lanthanum complexes based on a scorpionate ligand

Reaction of yttrium and lanthanum trichloride with 1 equiv of sodium or potassium hydrotris(3,5-dimethylpyrazolyl)borate and 1 equiv of 2,2'-bipyridine gives good yields of the complexes [MCl(2)(Tp(Me2))(C(10)H(8)N(2))] (M = Y (1), La (2)). The analogous compounds with 1,10-phenanthroline, [MCl(2)(Tp(Me2))(C(12)H(8)N(2))] (M = Y (3), La (4)), have been obtained by a similar procedure. The solid-state structures of 2-4 were determined by single-crystal X-ray diffraction and revealed that the compounds are all seven-coordinate with capped octahedral geometry. In contrast, reaction of yttrium trichloride with 1 equiv of sodium hydrotris(3,5-dimethylpyrazolyl)borate in the presence of 1 equiv of neocuproine affords [YCl(3)(Tp(Me2))][Na(neoc)(3))] (5). Compounds 1 and 2 provide an entry for the synthesis of complexes containing the bipyridyl ligand in a radical anionic form or in a dianionic form. Reaction of 1 and 2 with an excess of sodium amalgam gives [Y(Tp(Me2))(bipy)(THF)(2)] (6) and [La(Tp(Me2))(2)(bipy)] (7), respectively. The structures of both compounds have been determined by X-ray crystallography. Compound 7 can be oxidized with iodine to give [La(Tp(Me2))(2)(bipy)]I (8).     

Delineation of RAID1, the RACK1 interaction domain located within the unique N-terminal region of the cAMP-specific phosphodiesterase, PDE4D5

Background  

The cyclic AMP specific phosphodiesterase, PDE4D5 interacts with the β-propeller protein RACK1 to form a signaling scaffold complex in cells. Two-hybrid analysis of truncation and mutant constructs of the unique N-terminal region of the cAMP-specific phosphodiesterase, PDE4D5 were used to define a domain conferring interaction with the signaling scaffold protein, RACK1.