A vibrational spectroscopic investigation of rhodanine and its derivatives in the solid state

Raman and infrared spectra are reported for rhodanine, 3‐aminorhodanine and 3‐methylrhodanine in the solid state. Comparisons of the spectra of non‐deuterated/deuterated species facilitate discrimination of the bands associated with N H, NH₂, CH₂ and CH₃ vibrations. DFT calculations of structures and vibrational spectra of isolated gas‐phase molecules, at the B3‐LYP/cc‐pVTZ and B3‐PW91/cc‐pVTZ level, enable normal coordinate analyses in terms of potential energy distributions for each vibrational normal mode. The cis amide I mode of rhodanine is associated with bands at ∼1713 and 1779 cm⁻¹, whereas a Raman and IR band at ∼1457 cm⁻¹ is assigned to the amide II mode. The thioamide II and III modes of rhodanine, 3‐aminorhodanine and 3‐methylrhodanine are observed at 1176 and 1066/1078; 1158 and 1044; 1107 and 984 cm⁻¹ in the Raman and at 1187 and 1083; 1179 and 1074; 1116 and 983 cm⁻¹ in the IR spectra, respectively. Copyright © 2010 John Wiley & Sons, Ltd.     

Low Temperature Crystal Structures of Two Rhodanine Derivatives, 3-Amino Rhodanine and 3-Methyl Rhodanine: Geometry of the Rhodanine Ring

Abstract  Rhodanines (2-thio-4-oxothiazolidines) are synthetic small molecular weight organic molecules with diverse applications in biochemistry, medicinal chemistry, photochemistry, coordination chemistry and industry. The X-ray crystal structure determination of two rhodanine derivatives, namely (I), 3-aminorhodanine [3-amino-2-thio-4-oxothiazolidine], C₃H₄N₂OS_2, and (II) 3-methylrhodanine [3-methyl-2-thio-4-oxothiazolidine], C₄H₅NOS₂, have been conducted at 100 K. I crystallizes in the monoclinic space group P2₁/n with unit cell parameters a = 9.662(2), b = 9.234(2), c = 13.384(2) ?, β = 105.425(3)°, V = 1151.1(3) ?³, Z = 8 (2 independent molecules per asymmetric unit), density (calculated) = 1.710 mg/m³, absorption coefficient = 0.815 mm⁻¹. II crystallizes in the orthorhombic space group Iba2 with unit cell a = 20.117(4), b = 23.449(5), c = 7.852(2) ?, V = 3703.9(12) ?³, Z = 24 (three independent molecules per asymmetric unit), density (calculated) = 1.584 mg/m³, absorption coefficient 0.755 mm⁻¹. For I in the final refinement cycle the data/restraints /parameter ratios were 2639/0/161, goodness-of-fit on F² = 0.934, final R indices [I > 2sigma(I)] were R1 = 0.0299, wR2 = 0.0545 and R indices (all data) R1 = 0.0399, wR2 = 0.0568. The largest difference peak and hole were 0.402 and −0.259 e ?⁻³. For II in the final refinement cycle the data/restraints/parameter ratios were 3372/1/221, goodness-of-fit on F² = 0.950, final R indices [I > 2sigma(I)] were R1 = 0.0407, wR2 = 0.1048 and R indices (all data) R1 = 0.0450, wR2 = 0.1088. The absolute structure parameter = 0.19(9) and largest difference peak and hole 0.934 and −0.301 e ?⁻³. Details of the geometry of the five molecules (two for I and three for II) and the crystal structures are fully discussed. Corresponding features of the molecular geometry are highly consistent and firmly establish the geometry of the rhodanine ring. Index Abstract  Low temperature X-ray structures of (I) 3-aminorhodanine [3-amino-2-thio-4-oxothiazolidine] and (II) 3-methylrhodanine3-methyl-2-thio-4-oxothiazolidine are presented. Crystals of I are monoclinic and occupy space group P2₁/n with eight molecules (2 per asymmetric unit cell) and (II) is orthorhombic in space group Iba2 with 24 molecules (3 per asymmetric unit). This study has provided five highly consistent copies of the rhodanine ring at high resolution thus enabling its geometry to be established with confidence. The two independent molecules in the asymmetric unit of 3-aminorhodanine (left) and the three independent molecules in the asymmetric unit of 3-methylrhodanine (right) showing space filling and van der Waals contacts (drawn with MERCURY [Bruno et al. Acta Cryst B58:389, 2002]).     

Capillary electrophoresis and the clinical laboratory

Over the past 15 years, CE as an analytical tool has shown great promise in replacing many conventional clinical laboratory methods, such as electrophoresis and HPLC. CE's appeal was that it was fast, used very small amounts of sample and reagents, was extremely versatile, and was able to separate large and small analytes, whether neutral or charged. Because of this versatility, numerous methods have been developed for analytes that are of clinical interest. Other than molecular diagnostic and forensic laboratories CE has not been able to make a major impact in the United States. In contrast, in Europe and Japan an increasing number of clinical laboratories are using CE. Now that automated multicapillary instruments are commercially available along with cost-effective test kits, CE may yet be accepted as an instrument that will be routinely used in the clinical laboratories. This review will focus on areas where CE has the potential to have the greatest impact on the clinical laboratory. These include analyses of proteins found in serum and urine, hemoglobin (A1c and variants), carbohydrate-deficient transferrin, forensic and therapeutic drug screening, and molecular diagnostics.     

Development of new multifunctional terpolymer sorbent for proteomics applications

Determination of the availability of phases for specific separations is an important task achieved by a separation chemist. This becomes vital when the complex samples like biofluids are dealt with in proteome science. The work presented here involves the synthesis and application of terpolymeric sorbent with different functionalizations adopted for the selective enrichment of biomolecules of interest from biological fluids. Synthesis of terpolymer was carried out by the radical polymerization of monomers: methyl acrylate, acrylic acid and vinyl acetate with diethylene glycol dimethacrylate as cross‐linking agent, benzoyl peroxide as initiator and chloroform as a porogenic solvent. Characterization was done through Fourier transform infrared spectroscopy, scanning electron microscopy and nitrogen adsorption porosimetry. The polymer was further modified to immobilized metal ion affinity chromatographic material, with immobilized Fe³⁺/La³⁺ ions that allowed phosphopeptide enrichment from tryptic digests of standard proteins as well as milk, egg yolk and human serum. Sensitivity of enrichment down to 50 fmol was achieved in the presence of complex protein background as bovine serum albumin. Hydrophobicity was introduced through octadecyl amine, which provides comparable results to ZipTip C₁₈/C₄ for desalting of complex mixtures of all caseins. Analysis of the enriched content was performed by Matrix Assisted Laser Desorption Ionization Mass Spectrometry (MALDI‐MS). Copyright © 2014 John Wiley & Sons, Ltd.     

Synthesis,spectroscopic, theoretical study,and biological activities of vanadium(IV) and vanadium(V) complexes with isonipecotic acid

Russian Journal of General Chemistry - Vanadium(IV) and vanadium(V) complexes 1–7 have been synthesized by the reaction of isonipecotic acid with VOSO4 · 3 H2O, VCl3(THF)3, and NH4VO3 at...     

Composition of the essential oil of Origanum tyttanthum from Tajikistan

Origanum tyttanthum Gontsch. was collected from two different sites in south-central Tajikistan. The essential oils were obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry. A total of 52 compounds were identified representing 99.0-100% of total oil compositions. The major components of Origanum tyttanthum Gontsch. oil were carvacrol (34.3-59.2%), thymol (10.8-46.4%), p-cymene (0.7-7.3%), beta-thujone (1.9-4.1%), piperitenone oxide (0.1-3.8%), gamma-terpinene (0.3-3.5%), cis-piperitone epoxide (0.8-3.3%), carvacrol acetate (0.4-2.4%), menthone (0.6-2.1%) and borneol (1.0-2.3%).     

Boronic acid functionalized fibrous cellulose for the selective enrichment of glycopeptides

Enrichment of glycoproteins has been important because of their dynamicity and role in biological systems. Study of glycoproteins is complex because of the simultaneous glycosylation and deglycosylation inside the body. Often employed affinities for glycopeptides are hydrazide, boronic acid, or physiosorbed lectin on support materials. Cellulose, a natural polysaccharide, has rich surface chemistry, stable structure, low cost and availability in different variants. In present study, fibrous cellulose is oxidized using periodate to modify with boronic acid. Attachment of boronic acid is confirmed by Fourier transform infrared spectroscopy. Particle size and morphology of boronic acid@fibrous cellulose is studied by scanning electron microscopy. The enrichment efficiency is evaluated by using horseradish peroxidase as model protein. Boronic acid@fibrous cellulose is selective up to 1:250 for spiked horseradish peroxidase in bovine serum albumin digest, sensitive down to 0.1 femtomol and recovering 88.15% glycopeptides. Moreover, protein binding capacity is determined as 213 mg/g and 41% sequence coverage of horseradish peroxidase protein with all eight glycosylation sites detected. Total of 18 glycopeptides are enriched from immunoglobulin digest showing ability of boronic acid@fibrous cellulose to enrich glycoproteins from multiglycoforms. Enrichment from human serum recovers 18% extracellular and 72% secreted glycoproteins via bottom‐up approach and online tools.     

Thin-Layer Chromatographic Studies of the Mobility of Pesticides through Soil-Containing Static Flat-Beds

JPC – Journal of Planar Chromatography – Modern TLC - The chromatographic behavior of some pesticides has been studied on silica, soil, and mixed layers containing soil, with aqueous...     

Versatile nanocomposites in phosphoproteomics: A review

Protein phosphorylation is one of the most important post-translational modifications. Phosphorylated peptides are present in low abundance in blood serum but play a vital role in regulatory mechanisms and may serve as casual factors in diseases. The enrichment and analysis of phosphorylated peptides directly from human serum and mapping the phosphorylation sites is a challenging task. Versatile nanocomposites of different materials have been synthesized using simple but efficient methodologies for their enrichment. The nanocomposites include magnetic, coated, embedded as well as chemically derivatized materials. Different base materials such as polymers, carbon based and metal oxides are used. The comparison of nanocomposites with respective nanoparticles provides sufficient facts about their efficiency in terms of loading capacity and capture efficiency. The cost for preparing them is low and they hold great promise to be used as chromatographic materials for phosphopeptide enrichment. This review gives an overview of different nanocomposites in phosphoproteomics, discussing the improved efficiency than the individual counterparts and highlighting their significance in phosphopeptide enrichment.     

New coumarin from the roots of Prangos pabularia

The new coumarin 1, yuganin A (7-methoxy-8-((1S,2S)-1,2,3-trihydroxy-3-methylbutyl)-2H-chromen-2-one) along with nine known coumarins, heraclenol 3′-O-β-D-glucopyranoside (2), oxypeucedanin hydrate 3′-O-β-D-glucopyranoside (3), heraclenol (4), oxypeucedanin hydrate (5), osthole (6), oxypeucedanin (7), heraclenin (8), isoimperatorin (9), imperatorin (10) and the disaccharide sucrose (11), have been isolated from the roots of Prangos pabularia, and the structures of these isolated compounds were elucidated by spectroscopic means, especially, UV, HR-ESIMS, and 1D and 2D NMR spectroscopy. Furthermore, the anti-melanogenic effect of yuganin A and its inhibitory effect on B16 cells were evaluated. Yuganin A may be useful in the treatment of hyperpigmentation and as a skin-whitening agent in the cosmetics industry.