- DRUG-LOADED EMULSION
-
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.
- -
-
-
- Chemical dynamic kinetic resolution and S/R interconversion of unprotected α-amino acids
-
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.
-
supporting information
p. 12214 - 12217
(2016/02/18)
-
- Differentiation Among the Four Diastereomers of Benzyloxycarbonyl-protected γ-Hydroxyornithine in Negative-ion Fast Atom Bombardment Mass Spectrometry
-
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
-
p. 260 - 265
(2007/10/02)
-