38577-50-3Relevant articles and documents
A class of novel nitronyl nitroxide labeling basic and acidic amino acids: Synthesis, application for preparing ESR optionally labeling peptides, and bioactivity investigations
Zhang, Jianwei,Zhao, Ming,Cui, Guohui,Peng, Shiqi
, p. 4019 - 4028 (2008/12/22)
Aimed at optional ESR label 2-(4′-hydroxyl)phenyl-4,4,5,5-tetramethylimidazoline-3-oxide-1-oxyl was introduced into the guanido of l-Arg-OH, the ω-amino group of l-Lys-OH with methylcarboxyl as a linker, and into the β-carboxyl of l-Asp-OH and the γ-carboxyl of l-Glu-OH with ethylamino as a linker. It was explored that the synthetic 30 novel ESR labeling amino acid derivatives were stable enough to the reaction conditions of peptide synthesis. Their incorporation led to 12 novel ESR optionally labeling PAK, RGDS, RGDV, and ECG. A series of NO related chemical tests, the in vitro and in vivo assays of these peptides confirmed that this strategy was practical.
Novel 1-oxyl-2-substitutedphenyl-4,4,5,5-tetramethylimidazolines: Synthesis, selectively analgesic action, and QSAR analysis
Zhao, Ming,Li, Zheng,Peng, Li,Tang, Yu-Rong,Wang, Chao,Zhang, Ziding,Peng, Shiqi
, p. 2815 - 2826 (2007/10/03)
Based on the knowledge that imidazoline can result in analgesic action due to its selective binding with the prostacyclin receptor, 20 1-oxyl-2-substitutedphenyl-4,4,5,5-tetramethylimidazolines (3a-t) were prepared in moderate yields. At 0.13 mmol/kg dose, their in vivo analgesic activities were evaluated after the mice were administered at 30, 60, 90, and 150 min. Compared with the pain threshold (12.27 ± 9.56-17.71 ± 7.00%) of normal saline (NS) receiving mice, the pain threshold (23.42 ± 8.14% to 102.58 ± 10.66%) of 3a-t receiving mice increases significantly. Considering a prostacyclin receptor targeting analgesic agent usually had bleeding action and to appraise the bleeding risk, the in vivo tail bleeding time of 1.30 mmol/kg 3a-t receiving mice was found to be ranged from 116.3 ± 8.2 s to 120.3 ± 9.2 s, which was substantially equal to that (117.8 ± 8.4 s to 119.0 ± 8.6 s) of NS receiving mice. Based on the possibility of imidazoline acting as vasodilator, the in vitro vasorelaxations of 3a-t were tested using the rat aortic strip model. When the aortic strip contracted by noradrenaline (NE, final concentration 10-7 mol/l) was treated with 3a-t (final concentration 5 × 10-4 mol/l), only lower percentage inhibitions (6.55 ± 5.70-37.40 ± 4.07%) were recorded, implying that the vasorelaxation of 3a-t was neglectable. By selecting appropriate molecular descriptors generated from e-dragon server, the QSAR model of the analgesic activities of 3a-t was constructed using the multiple linear regression method. The established QSAR model showed reasonable accuracy and thus it is promising to be used for screening new 1-oxyl-2-substitutedphenyl-4,4,5,5-tetramethylimidazoline derivatives as analgesic agents.
Preparation and Characterization of New Chiral Nitronyl Nitroxides Bearing a Stereogenic Center in the Imidazolyl Framework
Shimono, Satoshi,Tamura, Rui,Ikuma, Naohiko,Takimoto, Tatsuya,Kawame, Naoyuki,Tamada, Osamu,Sakai, Naoko,Matsuura, Hiroaki,Yamauchi, Jun
, p. 475 - 481 (2007/10/03)
A synthetic procedure for optically active and racemic α-nitronyl nitroxides (α-NNs) having a stereogenic center at the 4-position of the imidazolyl ring is described. This procedure consists of (1) the synthesis of a dissymmetric vic-dinitro compound by Kornblum reaction, (2) the enantiomeric resolution of the racemate by a diastereomer method for obtaining the optically active sample, (3) the quick reduction of the optically active or racemic vic-dinitro compound to the bis(hydroxyamino) derivative with Al/Hg, (4) the solvent-free condensation of the bis(hydroxyamino) compound with an aldehyde to give the 1,3-dihydroxyimidazolidine, and (5) the final oxidation of the α-NN precursor with aqueous NaIO4. The absolute configuration of the optically active α-NNs was assigned by correlating with the X-ray crystal structure of the (-)- (1S,4R)-camphanic acid ester derivative of the optically active vic-dinitro compound. The molecular conformation of the optically active α-NNs was found to be folded both in solution and in the solid state by CD spectroscopy and energy minimization with the Monte Carlo method. The magnetic properties of both optically active and racemic α-NNs in solution and in the solid state were characterized by EPR spectroscopy and magnetic susceptibility measurement, respectively.
