68960-97-4Relevant articles and documents
PEGylated atorvastatin derivative and preparation method thereof
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Paragraph 0050; 0052, (2018/05/03)
The invention relates to a PEGylated atorvastatin derivative and a preparation method thereof. The method mainly comprises the following steps: 1) activating an end group of PEG; 2) enabling the activated PEG to react with atorvastatin to obtain an atorvastatin analogue. The structure of the atorvastatin analogue is: Atorvastatin-L-PEG-L-Atorvastatin, wherein Atorvastatin is atorvastatin; L is anester bond, an amido bond or other linking group; the PEG is residue of monodisperse polyethylene glycol; the structural formula of the atorvastatin analogue is shown in the description, where n is aninteger between 1 and 24. The preparation method has the advantages of short flow, easiness and convenience in reaction operation, few side reactions, low cost, high reaction selectivity, easiness inpurification and higher yield.
Optimization of the Sensitization Process and Stability of Octadentate Eu(III) 1,2-HOPO Complexes
D'Aléo, Anthony,Moore, Evan G.,Xu, Jide,Daumann, Lena J.,Raymond, Kenneth N.
, p. 6807 - 6820 (2015/08/03)
The synthesis of a series of octadentate ligands containing the 1-hydroxypyridin-2-one (1,2-HOPO) group in complex with europium(III) is reported. Within this series, the central bridge connecting two diethylenetriamine units linked to two 1,2-HOPO chromophores at the extremities (5-LIN-1,2-HOPO) is varied from a short ethylene chain (H(2,2)-1,2-HOPO) to a long pentaethylene oxide chain (H(17O5,2)-1,2-HOPO). The thermodynamic stability of the europium complexes has been studied and reveals these complexes may be effective for biological measurements. Extension of the central bridge results in exclusion of the inner-sphere water molecule observed for [Eu(H(2,2)-1,2-HOPO)]- going from a nonacoordinated to an octacoordinated Eu(III) ion. With the longer chain length ligands, the complexes display increased luminescence properties in aqueous medium with an optimum of 20% luminescence quantum yield for the [Eu(H(17O5,2)-1,2-HOPO)]- complex. The luminescence properties for [Eu(H(14O4,2)-1,2-HOPO)]- and [Eu(H(17O5,2)-1,2-HOPO)]- are better than that of the model bis-tetradentate [Eu(5LINMe-1,2-HOPO)2]- complex, suggesting a different geometry around the metal center despite the geometric freedom allowed by the longer central chain in the H(mOn,2) scaffold. These differences are also evidenced by examining the luminescence spectra at room temperature and at 77 K and by calculating the luminescence kinetic parameters of the europium complexes. (Graph Presented).
Catalysis in Aprotic Solvents. Inter- and Intramolecular Hydrogen Bonding Complexation
Ciuffarin, Ennio,Isola, Mauro,Leoni, Piero
, p. 3064 - 3070 (2007/10/02)
A mechanistic investigation is reported of aminolysis reactions of 2-hydroxy-5-nitro-α-toluenesulfonic acid sultone (1) in aprotic solvents.The n-butylaminolysis of 1 in acetonitrile and in toluene requires two and three molecules of amine, respectively.In the latter solvent, general bases strongly catalyze the reaction, and their catalytic constants are well correlated by the hydrogen bonding parameter pKHB.These results are interpreted by a multistep mechanism where each intermediate can be stabilized via hydrogen bonding by general bases.The mechanistic features depend on the stability of the intermediates and on the solvent characteristics.When diamines such as polyoxyethylenediamines H2NCH2(CH2OCH2)nCH2NH2 (2, n=2; 3, n=4; 4, n=6) are used as nucleophiles for the reaction with sultone 1 in toluene, much higher reactivities are observed when compared to reactions of monoamines and alkylenediamines.This represents a novel type of intramolecular catalysis due to intramolecular hydrogen bonding complexation between oxygen atoms and the ammonium group of the reaction intermediates (Scheme III).In toluene 2-4 also display a large basicity.
