- RADIATION ENHANCED MACROMOLECULAR DELIVERY OF THERAPEUTIC AGENTS FOR CHEMOTHERAPY
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Described herein are anti-cancer compounds composed of a macromolecule comprising (1) at least one anti-cancer agent directly or indirectly bonded to the macromolecule and (2) at least one high Z element directly or indirectly bonded to the macromolecule
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Paragraph 0068
(2016/07/05)
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- Synthesis of selenoxo peptides and oligoselenoxo peptides employing LiAlHSeH
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Synthesis of selenoxo peptides by the treatment of Nα- protected peptide esters with a combination of PCl5 and LiAlHSeH is delineated. The method is simple, high-yielding, and free from racemization. Thus obtained selenoxo peptides are used as units for N-terminal chain extension through Nα-deprotection/coupling to yield peptide-selenoxo peptide hybrids. Multiple selenation is demonstrated by conversion of two peptide bonds of tripeptides into selenoxo peptide bonds. Amino acid derived arylamides are also converted into aryl selenoamides. C6H 5-CSeNH-Val-OMe 8f is obtained as single crystal, and its structure was determined through X-ray diffraction study.
- Vishwanatha,Narendra,Chattopadhyay, Basab,Mukherjee, Monika,Sureshbabu, Vommina V.
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experimental part
p. 2689 - 2702
(2012/06/01)
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- Characterization of Nα-Fmoc-protected dipeptide isomers by electrospray ionization tandem mass spectrometry (ESI-MSn): Effect of protecting group on fragmentation of dipeptides
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A series of positional isomeric pairs of Fmoc-protected dipeptides, Fmoc-Gly-Xxx-OY/Fmoc-Xxx-Gly-OY (Xxx = Ala, Val, Leu, Phe) and Fmoc-Ala-Xxx-OY/Fmoc-Xxx-Ala-OY (Xxx = Leu, Phe) (Fmoc = [(9-fluorenylmethyl) oxy]carbonyl) and Y = CH3/H), have been characterized and differentiated by both positive and negative ion electrospray ionization ion-trap tandem mass spectrometry (ESI-IT-MSn). In contrast to the behavior of reported unprotected dipeptide isomers which mainly produce y 1+ and/or a1+ ions, the protonated Fmoc-Xxx-Gly-OY, Fmoc-Ala-Xxx-OY and Fmoc-Xxx-Ala-OY yield significant b 1+ ions. These ions are formed, presumably with stable protonated aziridinone structures. However, the peptides with Gly- at the N-terminus do not form b1+ ions. The [M + H]+ ions of all the peptides undergo a McLafferty-type rearrangement followed by loss of CO2 to form [M + H-Fmoc + H]+. The MS3 collision-induced dissociation (CID) of these ions helps distinguish the pairs of isomeric dipeptides studied in this work. Further, negative ion MS 3 CID has also been found to be useful for differentiating these isomeric peptide acids. The MS3 of [M-H-Fmoc + H]- of isomeric peptide acids produce c1-, z1 - and y1- ions. Thus the present study of Fmoc-protected peptides provides additional information on mass spectral characterization of the dipeptides and distinguishes the positional isomers. Copyright
- Ramesh,Raju,Srinivas,Sureshbabu,Vishwanatha,Hemantha
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experimental part
p. 1949 - 1958
(2012/05/20)
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- Understanding protease catalysed solid phase peptide synthesis
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A protease (thermolysin) was used to directly synthesise a number of dipeptides from soluble Fmoc-amino acids onto a solid support (PEGA1900) in bulk aqueous media, often in very good yields. This shift in equilibrium toward synthesis is remarkable because for soluble dipeptides in aqueous solution hydrolysis rather than synthesis is observed. Three possible reasons for the equilibrium shift were considered: (i) using a solid support makes it easy to use an excess of reagents, so mass action contributes towards synthesis; (ii) reduction in the unfavourable hydrophobic hydration of the Fmoc group within the solid support compared with the free amino acid in solution and (iii) suppression of the ionization of amino groups linked to the solid phase due to mutual electrostatic repulsion. It was found that under the conditions studied the second effect was most important.
- Ulijn, Rein V.,Bisek, Nicola,Halling, Peter J.,Flitsch, Sabine L.
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p. 1277 - 1281
(2007/10/03)
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- A mild and selective method for the cleavage of tert-butyl esters
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A method for the cleavage of t-butyl esters using silica gel in refluxing toluene is reported. Good yields of the corresponding carboxylic acids are obtained, and the reaction is selective for t-butyl esters over t-butyl ethers and trimethylsilylethyl (TMSE) esters.
- Jackson, Randy W
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p. 5163 - 5165
(2007/10/03)
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- Potential formation of intramolecular inclusion complexes in peptidocyclodextrins as evidenced by NMR spectroscopy
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Investigations of the structure of β- and γ-cyclodextrin derivatives in solution obtained by grafting amino acids or peptides are presented.These compounds are models for vectorization-dedicated molecular carriers.It is shown that for some amino acids, strong intramolecular self-inclusion complexes are formed in aqueous solution.This process strongly depends upon the nature and position of the pertinent amino acid in the peptide sequence.Two dimensional NMR experiments are used in conjunction with competition with external guests to evidence and estimate the strength of these auto-inclusion complexes.
- Djedaini-Pilard, Florence,Azaroual-Bellanger, Nathalie,Gosnat, Muriel,Vernet, Delphine,Perly, Bruno
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p. 723 - 730
(2007/10/02)
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- Synthesis of peptide derivatives of 5-fluorouracil
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The preparation of di-, tetra- and pentapeptides carrying 5-fluorouracil as an α-substituent of a terminal glycine moiety is described. The dipeptide compounds were synthetized by addition of ethyl glyoxylate to N-(benzyl-oxycarbonyl)-amino acid amides, s
- Nichifor, Marieta,Schacht, Etienne H.
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p. 3747 - 3760
(2007/10/02)
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