OBJECTIVETo study the influence of ligand structure on hydrolysis and solution stability of NAMI derivatives.

METHODNAMI type compound 1, trans- [RuCl4 (DMSO) (nica)] Na x 2DMSO (nica, nicotinamide) were prepared. Their hydrolytic mechanism, kinetics and stability were investigated by UV-Vis spectrophotometer.

RESULTSimilar to NAMI, compound 1 undergoes two well-separated steps chloro-hydrolysis (I chloro-hydrolysis and II chloro-hydrolysis) (step reaction) in pH 7.4 buffer solution; while dimethyl sulfoxide (DMSO) hydrolyze in pH 5.00 acetic buffer solution. The k(obs) and t1/2 for each hydrolytic reaction were determined.

CONCLUSIONThe stability of compound 1 in acidic solution is much more stable than that of in neutral solution. Nicotinamide in place of imidazole can decrease chloro hydrolytic rate of NAMI derivatives obviously, while the influence on the DMSO hydrolytic process is not so remarkable.

Dimethyl Sulfoxide ; chemistry ; Drug Stability ; Hydrolysis ; Imidazoles ; chemistry ; Kinetics ; Ligands ; Niacinamide ; chemistry ; Ruthenium ; chemistry ; Solutions ; chemistry

Recent concerns about the gradual depletion of conventional fossil resources and the pressure from global climate change have accentuated the need for new alternative feedstock. As one of the main components in biomass, lignin is the second most abundant natural polymer after cellulose, and has the potential to serve as a sustainable source of energy and organic carbon to replace petroleum-based chemicals. Efficient conversion of lignin into high value-added chemicals is crucial to improve the economic feasibility of biomass refinery. In the present study, several pretreatment technologies on industrial lignin were carried out to enhance phenol production. A microwave irradiation assisted biphasic reaction system was used to convert pretreated industrial lignin into phenolic compounds. Lignin conversion, reaction temperature, time and pretreatment method, were optimized. The highest phenol yield was 8.14% obtained from lignin pretreated by 1-ethyl-3-methylimidazolium acetate at 400 W for 60 min in a biophasic system catalyze by 1-aminoethyl-3-methylimidazolium tetrafluoroborate.
Biofuels ; Biomass ; Biotransformation ; Catalysis ; Imidazoles ; chemistry ; Lignin ; chemistry ; Phenols ; chemistry ; Temperature

AIMTo study the quantitative structure-activity relationship ( QSAR) of 23 tetrahydroimidazobenzodiazepinone (TIBO) as anti-HIV drug.

METHODSA newly developed three-dimensional holographic vector of atomic interaction field (3D-HoVAIF) was used to describe the chemical structure of anti-HIV drug-23 TIBO, a partial least square regression (PLS) model was built.

RESULTSThe obtained model with the cumulative multiple correlation coefficient (Rcum(2)), cumulative cross-validated (Qcum(2)) and standard error of estimation (SD) were Rcum(2) = 0. 824, Qcum(2) = 0.778 and SD = 0.56, respectively. The model had favorable estimation stability and good prediction capabilities.

CONCLUSIONSatisfactory results showed that 3D-HoVAIF with definite physic-chemical meanings and easy structural interpretation for structural characterization could preferably express information related to biological activity of TIBO.

Algorithms ; Anti-HIV Agents ; chemistry ; Benzodiazepines ; chemistry ; Holography ; methods ; Imidazoles ; chemistry ; Models, Molecular ; Quantitative Structure-Activity Relationship

The remarkable therapeutic success of PDE5 inhibitors in the treatment of male erectile dysfunction has focused the attention of the researchers on better defining the properties of the individual inhibitors and PDE5 that contribute to the high affinity of these inhibitors for interaction with the PDE5 catalytic site. Recent molecular studies have demonstrated that vardenafil has high affinity for PDE5 and low dissociation rate from PDE5, which serves to explain why vardenafil works with low dosage, onsets quickly and has curative action in clinical practice. Moreover, the potency of vardenafil depends on its ring structure that resembles the purine moiety in cGMP.
Drug Interactions ; Erectile Dysfunction ; drug therapy ; Humans ; Imidazoles ; chemistry ; pharmacology ; Male ; Molecular Structure ; Phosphodiesterase Inhibitors ; chemistry ; pharmacology ; Piperazines ; chemistry ; pharmacology ; Sulfones ; chemistry ; pharmacology ; Triazines ; chemistry ; pharmacology ; Vardenafil Dihydrochloride

Both AM1 semi-empirical quantum chemistry method and HF/3-21g* ab initio method were employed to get related parameters or descriptors, particularly, the parameters of the solvation energy delta G with polarizable continuum model, for 42 anti-HIV 5-phenyl-1-phenylamino-1H-imidazole derivatives with known cytotoxicity. With parameters of quantum chemical calculation and traditional ones, 2 multiple linear regression models were obtained. The better regression equation has a high correlation coefficient (r = 0.938) and a low standard deviation (s = 0.125) and the squared correlation coefficient Q2 of the cross-validation is 0.799 (literaure: 0.740) by leave-one-out method. The results have certain significance for the design of new anti-HIV-1 drugs with lower cytotoxicity.
Anti-HIV Agents ; chemistry ; pharmacology ; toxicity ; Imidazoles ; chemistry ; pharmacology ; toxicity ; Linear Models ; Models, Chemical ; Quantitative Structure-Activity Relationship

OBJECTIVETo establish residue analysis method of imidacloprid in Ephedra sinica by HPLC.

METHODImidacloprid was extracted with dichloromethane, cleaned up with chromatography column, then separated on Spherisorb C18 column by using Methanol-water (20:80), detected at 270 nm.

RESULT AND CONCLUSIONThe limit of detection (LOD) and limit quantification (LOQ) were 0.4 x 10(-9) g and 0.02 mg x kg(-1), mean recovery and related standard deviation (RSD) were 85.37%-90.65% and 2.23%-3.45%. It is concluded that the method could satisfy the pesticide residue analysis demands in sensitivity, accuracy and precision.

Chromatography, High Pressure Liquid ; methods ; Ephedra sinica ; chemistry ; Imidazoles ; analysis ; Insecticides ; analysis ; Neonicotinoids ; Nitro Compounds ; analysis ; Pesticide Residues ; analysis ; Plants, Medicinal ; chemistry ; Reproducibility of Results

AIMDesign, synthesis and evaluation of a series of 7-imidazolylalkanamido-1-carboxylalkylbenzodiazepine farnesyltransferase (FTase) inhibitors.

METHODS AND RESULTSCoupling of imidazolylalkylcarboxylic acids and 1-substituted 7-aminobenzodiazepines (5a-5c) yielded 10 new compounds (6-12, 16-18) which were biologically tested against FTase using scintillation proximity assay method.

CONCLUSIONFive target compounds were found to be potential farnesyltransferase inhibitors.

Alkyl and Aryl Transferases ; antagonists & inhibitors ; drug effects ; Benzodiazepines ; chemical synthesis ; chemistry ; pharmacology ; Farnesyltranstransferase ; Imidazoles ; chemical synthesis ; chemistry ; pharmacology ; Inhibitory Concentration 50 ; Molecular Conformation ; Molecular Structure ; Structure-Activity Relationship

Anti-HBcAg monoclonal antibodies from mouse ascites were purified by using immobilized metal ion affinity chromatography. We optimized the conditions of sample loading and elution. The results showed that when the pH stepwise elution was used, the best solution for sample loading was 20 mmol/L phosphate buffer containing 0.5 mol/L sodium chloride at pH 8.0 and the mAb was eluted at pH 5.0. The purity of obtained mAb was more than 85% and recovery reached 80%. When the adsorbed proteins were eluted by using gradient elution of an imidazole, the best solution for loading condition was 20 mmolL phosphate buffer containing 5 mmol/L imidazole at pH 8.0. The purity and recovery of antibody were up to 95%.
Animals ; Antibodies, Monoclonal ; isolation & purification ; Chromatography, Affinity ; methods ; Chromatography, Ion Exchange ; methods ; Hepatitis B Core Antigens ; immunology ; Hydrogen-Ion Concentration ; Imidazoles ; chemistry ; Metals ; chemistry ; Mice

Polyamides, containing N-methylpyrrole (Py) and N-methyl-imidazole (Im) amino acids, are synthetic oligomers programmed to read the DNA double helix in the minor groove with high affinities and sequence specificities resulting in modulation of gene expression. They are cell permeable, stable and have no cytotoxicity, which provide a promising tool of gene regulation. We describe here recent advances in the field of DNA binding polyamides, including pairing rules, specifities and affinities to DNA, synthesis methods, cellular and nuclear uptake properties, gene regulation and effectiveness in vivo. The potential problems and difficulties in future research are also discussed.
Animals ; Base Pairing ; DNA ; chemistry ; genetics ; DNA Footprinting ; Gene Expression Regulation ; drug effects ; Imidazoles ; chemical synthesis ; chemistry ; metabolism ; pharmacology ; Nylons ; chemical synthesis ; chemistry ; metabolism ; pharmacology ; Pyrroles ; chemical synthesis ; chemistry ; metabolism ; pharmacology

To evaluate the reagent 2-methoxy-4,5-dihydro-1H-imidazole used for isotopic labeling in quantitative proteomics, we synthesized 2-methoxy-4,5-dihydro-1H-imidazole and its tetradeuterated analog in three steps. Prior to tryptic cleavage, bovine serum albumin (BSA) was reduced and alkylated. Tryptic peptides were derivatized with an equal volume of either DO or D4 and D4-derivatized peptides were mixed with at variable ratio (from 10:1 to 1:5) prior to MS and MS/MS analysis. We used matrix assisted laser desorption/ionization-mass spectrometry (MALDI-MS) and Electro spray ionization-mass spectrometry (ESI-MS) to evaluate the quantitative capability of labeling. The specificity of the reagent is excellent: only lysine side chains were modified among tryptic peptides. MALDI and ESI ionization modes not only could achieve the quantification of differentially expressed proteins but also facilitate the de novo sequencing. This side-chain modification can be used for quantitative analysis with proteomic strategies involving liquid chromatography. Reverse phase liquid chromatography (RPLC) kept a good resolution, and the introduction of D atoms did not introduce a variation of retention time between heavy and light peptides in RPLC.
Imidazoles ; chemistry ; Isotope Labeling ; methods ; Lysine ; chemistry ; Peptides ; analysis ; chemistry ; Proteomics ; methods ; Serum Albumin, Bovine ; chemistry ; Spectrometry, Mass, Electrospray Ionization ; methods ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; methods