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Different Reagents (different + reagent)
Selected AbstractsN -[4-(dicyanomethylazo)phenyl]-2-saccharin-2-ylacetamide in the synthesis of pyridazine and pyrimidine derivativesHETEROATOM CHEMISTRY, Issue 1 2004A. A. Aly N -[4-(Dicyanomethylazo)phenyl]-2-saccharin-2-ylacetamide (2) proved to be a convenient precursor for the synthesis of a variety of pyridazine and pyrimidine derivatives 4a,b,6, and 7. Also a series of substituted pyrimidines 10,16 were prepared from the reaction of N -[4-(2-amino-1-cyano-2-substitutedvinylazo)phenyl]-2-(saccharin-2-yl)acetamide 9a,b with different reagents via initial addition to either the cyano or amino group, followed by cyclization. Some of the synthesized heterocycles were screened for their biological activity. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 15:2,8, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10194 [source] Poly(styrene- co -glycerol dimethacrylate): Synthesis, characterization, and application as a resin for gel-phase peptide synthesisJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 19 2005Michael Roice Abstract An efficient cross-linked polymer support for solid-phase synthesis was prepared by introducing glycerol dimethacrylate cross-linker to polystyrene network using free radical aqueous suspension polymerization. The support was characterized by various spectroscopic methods. Morphological feature of the resin was analyzed by microscopy. The polymerization reaction was investigated with respect to the effect of amount of cross-linking agent, which in turn vary the swelling, loading, and the mechanical stability of the resin. The solvent uptake of the polymer was studied in relation to cross-linking and compared with Merrifield resin. The stability of the resin was tested in different synthetic conditions used for solid-phase peptide synthesis. Hydroxy group of the support was derivatized to chloro and then amino groups using different reagents and reaction conditions. Efficiency of the support was tested and compared with TentaGelÔ resin by following different steps involved in the synthesis of the 65,74 fragment of acyl carrier protein. The results showed that the poly(styrene- co -glycerol dimethacrylate) (GDMA-PS) is equally efficient as TentaGel resin in peptide synthesis. The purity of the peptides was analyzed by HPLC and identities were determined by mass spectroscopy and amino acid analysis. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4382,4392, 2005 [source] Effect of adlay (Coix lachryma-jobi L. var. ma-yuen Stapf.) hull extracts on testosterone release from rat Leydig cellsPHYTOTHERAPY RESEARCH, Issue 5 2009Shih-Min Hsia Abstract Adlay has been used as a traditional Chinese medicine for the treatment of many diseases. However, few studies have reported the effects of adlay seeds on the endocrine system. In the present study, the effects of methanol extracts of adlay hull (AHM) on testosterone synthesis were studied. Rat Leydig cells were incubated with different reagents including human chorionic gonadotropin, 8-bromo-adenosine-3,,5,-cyclic monophosphate, forskolin, A23187, progesterone and androstenedione in the presence or absence of AHM. The rat anterior pituitary (AP) gland was treated with gonadotropin-releasing hormone (GnRH) in vitro in the presence or absence of AHM, and the concentrations of luteinizing hormone (LH) in the media were measured. AHM decreased testosterone release via the inhibition of (1) the PKA and PKC signal transduction pathways, (2) 17, -HSD enzyme activity in rat Leydig cells, and (3) in vitro GnRH-induced LH secretion. Copyright © 2008 John Wiley & Sons, Ltd. [source] Spin State, Structure, and Reactivity of Terminal Oxo and Dioxygen Complexes of the (PNP)Rh MoietyCHEMISTRY - A EUROPEAN JOURNAL, Issue 25 2008Alexander Abstract [RhIIIH{(tBu2PCH2SiMe2NSiMe2CH2PtBu{CMe2CH2})}], ([RhH(PNP*)]), reacts with O2 in the time taken to mix the reagents to form a 1:1 ,2 -O2 adduct, for which OO bond length is discussed with reference to the reducing power of [RhH(PNP*)]; DFT calculations faithfully replicate the observed O,O distance, and are used to understand the oxidation state of this coordinated O2. The reactivity of [Rh(O2)(PNP)] towards H2, CO, N2, and O2 is tested and compared to the associated DFT reaction energies. Three different reagents effect single oxygen atom transfer to [RhH(PNP*)]. The resulting [RhO(PNP)], characterized at and above ,60,°C and by DFT calculations, is a ground-state triplet, is nonplanar, and reacts, above about +15,°C, with its own tBu CH bond, to cleanly form a diamagnetic complex, [Rh(OH){N(SiMe2CH2PtBu2)(SiMe2CH2PtBu{CMe2CH2})}]. [source] Fast chiral separation of drugs using columns packed with sub-2 ,m particles and ultra-high pressureCHIRALITY, Issue 3 2010Davy Guillarme Abstract The use of columns packed with sub-2 ,m particles in liquid chromatography with very high pressure conditions (known as UHPLC) was investigated for the fast enantioseparation of drugs. Two different procedures were evaluated and compared using amphetamine derivatives and ,-blockers as model compounds. In one case, cyclodextrins (CD) were directly added to the mobile phase and chiral separations were carried out in less than 5 min. However, this strategy suffered from several drawbacks linked to column lifetime and low chromatographic efficiencies. In the other case, the analysis of enantiomers was carried out after a derivatization procedure using two different reagents, 2,3,4-tri-O-acetyl-,- D -arabinopyranosyl isothiocyanate (AITC) and N -,-(2,4-dinitro-5-fluorophenyl)- L -alaninamide (Marfey's reagent). Separation of several amphetamine derivatives contained within the same sample was achieved in 2,5 min with high efficiency and selectivity. The proposed approach was also successfully applied to the enantiomeric purity determination of (+)-(S)-amphetamine and (+)-(S)-methamphetamine. Similar results were obtained with ,-blockers, and the separation of 10 enantiomers was carried out in less than 3 min, whereas the individual separation of several ,-blocker enantiomers was performed in 1 min or less. Chirality, 2010. © 2009 Wiley-Liss, Inc. [source] Effect of intramolecular interactions on circular dichroism of ortho-substituted 1-phenethylamines,CHIRALITY, Issue 8 2004V.M. Demyanovich Abstract The synthesis of ortho-substituted (S)-1-phenethylamines via ortho-lithiation of its N,N-dimethyl derivative followed by reactions with different reagents is described. Circular dichroism spectra of synthesized compounds were measured. It is shown that the observed short-wave Cotton effects greatly depend on the existence of cyclic structure due to possible interactions such as hydrogen bond or electrostatic interaction. Chirality 16:486,492, 2004. © 2004 Wiley-Liss, Inc. [source] | ||||||||||