- 4-(4,6-Dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium Toluene-4-sulfonate (DMT/NMM/TsO?) Universal Coupling Reagent for Synthesis in Solution
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4-(4,6-Dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium toluene-4-sulfonate (DMT/NMM/TsO?), a representative member of the inexpensive and environmentally-friendly N-triazinylammonium family of sulfonates, has been found to be a very effective coupling reagent for the synthesis of amides, esters and peptides in solution. This study confirms the usefulness of DMT/NMM/TsO? for peptide synthesis in solution, starting from Z-, Fmoc-, and Boc-protected substrates as well as unnatural building blocks. Peptide synthesis with DMT/NMM/TsO? produced high yields, with high crude product purity and low risk of racemization. In all cases, stoichiometric amounts of reagents were used and the standard synthetic procedure, without the need for time-consuming optimization stages or expensive chromatographic purification. DMT/NMM/TsO? was also found to be very useful for the synthesis of oligopeptides using a fragment coupling strategy.
- Fraczyk, Justyna,Kaminski, Zbigniew J.,Katarzynska, Joanna,Kolesinska, Beata
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- N-triazinylammonium tetrafluoroborates. A new generation of efficient coupling reagents useful for peptide synthesis
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A new generation of triazine-based coupling reagents (TBCRs), designed according to the concept of "superactive esters", was obtained by treatment of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium (DMTMM) chloride with lithium or silver tetrafluoroborate. The structure of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium tetrafluoroborate was confirmed by X-ray diffraction. Activation of carboxylic acids by using this reagent proceeds via triazine "superactive ester". The coupling reagent was successfully used for the synthesis of Z-, Boc-, and Fmoc-protected dipeptides derived from natural and unnatural sterically hindered amino acids and for fragment condensation, in 80-100% yield and with high enantiomeric purity. The manual SPPS of the ACP(65-74) peptide fragment (H-Val-Gln-Ala-Ala- lle-Asp-Tyr-Ile-Asn-Gly-OH) proceeded significantly faster than with TBTU or HATU, as well as the automated SPPS of the same fragment gave a purer product than by using TBTU or PyBOP. The reagent was also demonstrated to be efficient in on-resin head-to-tail cyclization of constrained cyclopeptides, in SPPS synthesis of Aib peptides, and in the synthesis of esters from appropriate acids, alcohols, and phenols. The high efficiency and versatility of this new generation of TBCRs confirm, for the first time, the usefulness of the concept of "superactive esters" in rational design of the structure of coupling reagents.
- Kaminski, Zbigniew J.,Kolesinska, Beata,Kolesinska, Justyna,Sabatino, Giuseppina,Chelli, Mario,Rovero, Paolo,Blaszczyk, Michal,Glowka, Marek L.,Papini, Anna Maria
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p. 16912 - 16920
(2007/10/03)
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- P-toluenosulfonate salt of N-Methyl-N-(3,5-dimathoxy-2,4,6-triazinyl-1-)-morpholine and related compounds for use as condensing reagent in peptide synthesis
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The invention refers to new quarternary N-(3,5-disubstituted-1,3,5-triazinyl-1)-ammonium salts of sulfonic acids, with formula 1, where R1 and R2 denote in total or independently a halogen atom, an alkyl group, a substituted alkyl gr
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Page/Page column 5-6
(2008/06/13)
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- In vitro and in vivo evaluations of THAM derived telomers bearing RGD and Ara-C for tumour neovasculature targeting
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As an approach to the development of specific drug delivery systems, a new class of low macromolecular carriers called 'telomers' endowed with an antitumour agent, such as arabinofuranosylcytosine (Ara-C), RGDSK peptidic sequences, as tumour targeting moieties, and tyrosine groups labelled with 125I atoms allowing the in vivo scintigraphic follow up, were synthesized. Their tumour targeting ability was assessed in vivo in mice bearing a murine B16 melanoma. The biological results showed that the presence of RGDSK sequences onto the macromolecules leads to the selective targeting and the accumulation of telomers within the vascularized zone of the tumour. Moreover, such compounds exhibited in vitro a better IC50 (0.015 μM) than pure Ara-C and in vivo an oncostatic index higher than 160%.
- Jasseron,Contino-Pepin,Maurizis,Rapp,Pucci
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p. 825 - 836
(2007/10/03)
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- Preparation of glycosyl amino acids as building blocks for the combinatorial synthesis of neoglycoconjugates
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Several neoglycosyl amino acids possessing a sugar residue, a spacer and a trifunctional amino acid moiety were synthesized both in solution and solid phase by activating the carboxylic group as its pentafluorophenyl ester for condensation. The methodolog
- Ziegler, Thomas,Roeseling, Dirk,Subramanian, Lakshminarayanapuram R.
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p. 911 - 914
(2007/10/03)
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- PREPARATION OF PENTAFLUOROPHENYL ESTERS OF FMOC PROTECTED AMINO ACIDS WITH PENTAFLUOROPHENYL TRIFLUOROACETATE
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A high yield procedure for the preparation of pentafluorophenyl esters of Nα-9-fluorenylmethyloxycarbonyl protected amino acids is described.The procedure utilizes pentafluorophenyl trifluoroacetate.
- Green, Michael,Berman, Judd
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p. 5851 - 5852
(2007/10/02)
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- 9-Fluorenylmethyl Pentafluorophenyl Carbonate as a Useful Reagent for the Preparation of N-9-Fluorenylmethyloxycarbonylamino Acids and their Pentafluorophenyl Esters
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9-Fluorenylmethyl pentafluorophenyl carbonate is a useful reagent for the efficient, side reaction-free introduction of N-9-fluorenylmethyloxycarbonyl protecting group into amino acids and for the subsequent preparation of their pentafluorophenyl esters.Some new compounds of both types are described.
- Schoen, Istvan,Kisfaludy, Lajos
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p. 303 - 305
(2007/10/02)
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