Two Aromatic Ester Organoimido Derivatives of Hexa­molybdate: Syntheses,Crystal Structures,and Spectroscopic Studies

Two alkylimido derivatives of hexamolybdate, (Bu₄N)₂[Mo₆O₁₈(≡N‐o‐COOCH₃C₆H₄)] ( 1 ) and (Bu₄N)₂[Mo₆O₁₈(≡N‐o‐COOCH₂CH₃C₆H₄)] ( 2 ), were synthesized in high purity and good yields by the reaction of [(C₄H₉)₄N]₄[α‐Mo₈O₂₆] and methyl anthranilate or ethyl‐o‐aminobenzoate hydrochloride with N,N′‐dicyclohexylcarbodiimide (DCC) as a dehydrating agent in dry acetonitrile solution, which were characterized by elemental analyses, IR, UV/Vis, and ¹H NMR spectroscopy as well as ESI‐MS, and single‐crystal X‐ray diffraction study. Compound 1 crystallizes in the monoclinic space group P2₁/n with one‐dimensional chain structure via intramolecular hydrogen bond. Compound 2 also crystallizes in the monoclinic space group P2₁/n with dimer structure by intramolecular hydrogen bonds and π–π interactions between the pairs of cluster anions.     

Vibrational spectroscopy and DFT calculations of N,N′‐dicyclohexylcarbodiimide

Infrared (IR) and Raman spectra were obtained for N,N′‐dicyclohexylcarbodiimide (DCC) in the solid state and in CHCl₃ solution. Structures and vibrational spectra of isolated, gas‐phase DCC molecules with C₂ and C_i symmetries, computed at the B3‐LYP/cc‐pVTZ level, show that the IR and Raman spectra provide convincing evidence for a C₂ structure in both the solid state and in CHCl₃ solution. Using a scaled quantum‐chemical force field, these density functional theory calculations have provided detailed assignments of the observed IR and Raman bands in terms of potential energy distributions. Comparison of solid‐state and solution spectra, together with a Raman study of the melting behaviour of DCC, revealed that no solid‐state effects were evident in the spectra. Copyright © 2010 John Wiley & Sons, Ltd.     

Bioactive polymers XXI. Coupling of chloramphenicol on Biozan R

The coupling of chloramphenicol on Biozan R (Hercules) by activation with dicyclohexylcarbodiimide was studied. The esterification is influenced by the chloramphenicol/dicyclohexylcarbodiimide ratio, concentration of the reactants and reaction time.The microbial tests performed with products of different chloramphenicol contents attest their antimicrobial activity and their possible use, especially in ophtalmology.     

Reactions of cis-2-Boryl-1-stannylalkenes with Carbodiimides, Thiocyanates, Isothiocyanates, and Isocyanates

The reactions of (E)-2-diethylboryl-1-trimethylstannylbut-1-ene and (Z)-3-diethylboryl-2-trimethylstannylpent-2-ene with carbodiimides, methyl thiocyanate, thioisocyanates, and isocyanates were studied, and the products were characterized by multinuclear magnetic resonance spectroscopy (¹H, ¹¹B, ¹³C and ¹¹⁹Sn NMR). It was found that carbodiimides bearing tert-butyl or trimethylsilyl groups at the nitrogen atoms do not react with (E)-2-boryl-1-stannylalkenes, in contrast to dicyclohexylcarbodiimide. There was also no reaction in the case of MeSCN. All other reactions proceed via a weak NB adduct formation in the initial step, followed by different rearrangements, depending on the structure of reagents as well as on the substitution pattern at the C=C bond in alkenes. New heterocycles are formed, in which the boron atom is either tricoordinated (1,2-azaborolenes, 1,2-azaborolan! es), a nd one ethyl group has been transferred to the neighbor olefinic carbon atom, or the boron atom is tetracoordinated (1,2-azaboratoles, 1,2-oxoniaboratoles), and the trimethylstannyl group has migrated to one of the heteroatoms of the heterocumulenes.     

Focused microwave irradiation-assisted synthesis of N-cyclohexyl-1,2,4-oxadiazole derivatives with antitumor activity

A facile synthesis of 3,5-disubstituted 1,2,4-oxadiazole derivatives under focused microwave irradiation (FMWI) is reported. Arylamidoximes 1a–i and dicyclohexylcarbodiimide (DCC) were carried out in DMF under FMWI to obtain 1,2,4-oxadiazoles 2a–i in 61–81% yields. All compounds exhibited antiproliferative activities in vitro against three human cancer cell lines HCT-116, PC-3, and SNB-19.     

1,3-二环基碳化二亚胺催化的阿魏酸对硝基苯酚酯一步合成法

1;3-二环基碳化二亚胺催化的阿魏酸对硝基苯酚酯一步合成法;酯化反应     

Production of monoclonal antibodies against hop-derived (Humulus lupulus L.) prenylflavonoids and the development of immunoassays

Monoclonal antibodies against the hop-derived prenylated chalcone xanthohumol (X) and the prenylated flavonoids isoxanthohumol (IX) and 8-prenylnaringenin (8-PN) were developed. Carboxylic acid haptens of X, IX and 8-PN were synthesized by linking a spacer to their C4′-OH group followed by subsequent coupling to bovine serum albumin (BSA) to form conjugates that were employed as immunogens in BALB/c mice to raise antibodies. The monoclonal antibodies that were secreted from the established hybridoma cell lines proved, in cross-reactivity studies, to possess highly specific binding capacities in an optimized competitive indirect ELISA. The immunoassays make use of immunogen-coated microtiterplates and a peroxidase-labeled anti-mouse IgG₁ secondary antibody with ABTS as a chromogenic substrate. For X the IC₅₀ value derived from the standard curve was 62.91 ng mL⁻¹, and for both IX and 8-PN 37.15 ng mL⁻¹. The assay was validated for the quantitative analysis of X, IX and 8-PN in urine and serum. A simple sample pretreatment procedure using a diethyl ether extraction was optimized and the recoveries and matrix effects were assessed. The validity of the established assay was tested and mean inter- and intra-assay variations in urine were 2.32% and 1.91%, respectively for X, 6.24% and 2.39%, respectively for IX and 7.18% and 0.74%, respectively for 8-PN. In serum, the mean inter- and intra-assay variations were 8.90% and 1.37%, respectively for X, 6.13% and 1.57%, respectively for IX and 6.13% and 2.43%, respectively for 8-PN. Furthermore, the method demonstrated excellent accuracy and significant correlation with measurements by an established and validated HPLC-MS method.     

用苯乙烯共聚的方法改性含硫光学树脂的研究

自１９７２年美国ＦＤＡ制定有关配戴镜片的安全性规定以来，镜片的安全性正日益受到重视［１］．聚合物光学材料由于具有质轻、耐破损、价格便宜、易加工成型等优点［１～３］，近年来被广泛用于制作各种眼镜镜片和光学仪器的透镜［４］．对这类材料的要求除具有优良的机...     

Fluorinated peptidomimetics: synthesis, conformational and biological features

Peptides modified with fluoroalkyl functions in key backbone positions have been scarcely studied so far. Thus, little is known about their synthesis, their structural and physico-chemical properties, and their biological features. Our interest in this field of research led to the development of stereocontrolled synthetic protocols, both in solution and in solid phase, for many different fluoroalkyl peptidomimetics, some of which are overviewed in this paper: (a) ψ[CH(CF₃)NH]-peptide mimics holding a great potential as hybrids between natural peptides and hydrolytic transition state analogs; (b) trifluoromethyl (Tfm) malic peptidomimetics as micromolar inhibitors of some matrix metalloproteinases; (c) bis-Tfm analogs of Pepstatin A, that are nanomolar and selective inhibitors of the protozoal aspartyl protease Plasmepsin II.