- DRUG-LOADED EMULSION
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The present invention relates to a drug-loaded emulsion, comprising a modified hydrophobic excipient having the following formula, a hydrophobic drug and a surfactant: where R is a hydrophobic natural compound or a hydrophobic synthetic compound with one to three hydroxyl groups (n=1-3); and R1 is an α-amino protecting group, and R2 is an amino acid side chain, wherein, when m=0, R is reacted with an amino acid derivative with a protecting group by esterification to form a hydrophobic excipient carrying the amino acid derivative with a protecting group; or when m=1, R is firstly introduced with an amino acid linking arm of different chain lengths (l=1, 2, 4, 6) via an ester group, and then introduced with an amino acid derivative with a protecting group.
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- Chemical dynamic kinetic resolution and S/R interconversion of unprotected α-amino acids
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Reported herein is the first purely chemical method for the dynamic kinetic resolution (DKR) of unprotected racemic α-amino acids (α-AAs), a method which can rival the economic efficiency of the enzymatic reactions. The DKR reaction principle can be readily applied for S/R interconversions of α-AAs, the methodological versatility of which is unmatched by biocatalytic approaches. The presented process features a virtually complete stereochemical outcome, fully recyclable source of chirality, and operationally simple and convenient reaction conditions, thus allowing its ready scalability. A quite unique and novel mode of the thermodynamic control over the stereochemical outcome, including an exciting interplay between axial, helical, and central elements of chirality is proposed. A new player for DKR: Dynamic kinetic resolution of α-amino acids has been achieved upon complexation with nickel(II) and a chiral ligand derived from optically active bis(naphthyl)amine under thermodynamic control, thus affording excellent diastereoselectivities and chemical yields. The S to R interconversion of α-amino acids is also described.
- Takeda, Ryosuke,Kawamura, Akie,Kawashima, Aki,Sato, Tatsunori,Moriwaki, Hiroki,Izawa, Kunisuke,Akaji, Kenichi,Wang, Shuni,Liu, Hong,Ace?a, José Luis,Soloshonok, Vadim A.
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supporting information
p. 12214 - 12217
(2016/02/18)
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- Synthesis, screening and docking of small heterocycles as Glycogen Phosphorylase inhibitors
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A series of morpholine substituted amino acids (phenylalanine, leucine, lysine and glutamic acid) was synthesized. A fragment-based screening approach was then used to evaluate a series of small heterocycles, including morpholine, oxazoline, dihydro-1,3-oxazine, tetrahydro-1,3-oxazepine, thiazoline, tetrahydro-1,3-pyrimidine, tetrahydro-1,3-diazepine and hexahydro-1H-benzimidazole, as potential inhibitors of Glycogen Phosphorylase a. Thiazoline 7 displayed an improved potency (IC50 of 25 μM) and had good LE and LELP values, as compared to heterocycles 1, 5, 9e13 and 19 (IC50 values of 1.1 mM e23.9 mM). A docking study using the crystal structure of human liver Glycogen Phosphorylase, provided insight into the interactions of heterocycles 5, 7, 9e13 and 19 with Glycogen Phosphorylase.
- Schweiker, Stephanie S.,Loughlin, Wendy A.,Lohning, Anna S.,Petersson, Maria J.,Jenkins, Ian D.
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p. 584 - 594
(2015/03/14)
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- Differentiation Among the Four Diastereomers of Benzyloxycarbonyl-protected γ-Hydroxyornithine in Negative-ion Fast Atom Bombardment Mass Spectrometry
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Discrimination among the four γ-hydroxyornithine diastereomers was studied by fast atom bombardment mass spectrometry (FABMS).It is impossible to distinguish among the four diastereomers of this amino acid by positive- and negative-ion FAB and collisionally activated dissociation MS, but benzyloxycarbonyl group protection of the α- and δ-amino groups in γ-hydroxyornithine allows differentiation among the diastereomers in negative-ion FABMS.The negative-ion mass spectra of benzyloxycarbonyl-protected γ-hydroxyornithine diastereomers showed differences among the abundances of the molecule ion (-), the dehydrated ion (-) due to the loss of the γ-hydroxyl group and the fragment ions formed from both (-) and (-) ions.On the other hand, no difference was found between the fragmentations of the benzyloxycarbonyl-protected enantiomers of ornithine in negative-ion FABMS.These results indicate that the orientation of the γ-hydroxyl group and the existence of two benzene rings in the benzyloxycarbonyl group are important factors which are responsible for the fragmentations of the four benzyloxycarbonyl-protected γ-hydroxyornithine diastereomers in negative-ion FABMS.These studies also showed that the negative-ion FABMS for benzyloxycarbonyl-protected γ-hydroxyornithine diastereomers is a useful method for determining the configuration of each diastereomer of γ-hydroxyornithine.
- Tsunematsu, Hideaki,Isobe, Ryuichi,Mizusaki, Koichi,Makisumi, Satoru,Yamamoto, Magobei
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p. 260 - 265
(2007/10/02)
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