189455-66-1Relevant articles and documents
Characterization of Nα-Fmoc-protected dipeptide isomers by electrospray ionization tandem mass spectrometry (ESI-MSn): Effect of protecting group on fragmentation of dipeptides
Ramesh,Raju,Srinivas,Sureshbabu,Vishwanatha,Hemantha
, p. 1949 - 1958 (2011)
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
A simple method for the generation of chloromethyl polystyrene on the Multipin(TM) solid support
Bui, Chinh T.,Maeji, N. Joe,Rasoul, Firas,Bray, Andrew M.
, p. 5383 - 5386 (1999)
A novel route for the chloromethylation of polystyrene grafted Multipin supports (Synphase(TM) Crowns) has been developed. Aminomethylated polystyrene was converted into chloromethylated polystyrene via a simple diazotisation reaction. The modified graft polymer was assessed by solid phase synthesis of a model dipeptide.
Isostearyl Mixed Anhydrides for the Preparation of N-Methylated Peptides Using C-Terminally Unprotected N-Methylamino Acids
Cary, Douglas R.,Handa, Michiharu,Kobayashi, Yutaka,Kurasaki, Haruaki,Masuya, Keiichi,Matsuda, Ayumu,Matsumoto, Masatoshi,Morimoto, Koki,Nagaya, Akihiro,Nishizawa, Naoki,Taguri, Tomonori,Takeuchi, Hisayuki
supporting information, p. 8039 - 8043 (2020/11/02)
Sustainable and efficient manufacturing methods for N-methylated peptides remain underexplored despite growing interest in therapeutic N-methylated peptides within the pharmaceutical industry. A methodology for the coupling of C-terminally unprotected N-methylamino acids mediated by an isostearic acid halide (ISTAX) and silylating reagent has been developed. This approach allows for the coupling of a wide variety of amino acids and peptides in high yields under mild conditions without the need for a C-terminal deprotection step in the process of C-terminal elongation. These advantages make this a useful synthetic method for the production of peptide therapeutics and diagnostics containing N-methylamino acids.
Heating and microwave assisted SPPS of C-terminal acid peptides on trityl resin: The truth behind the yield
Echalier, Cecile,Al-Halifa, Soultan,Kreiter, Aude,Enjalbal, Christine,Sanchez, Pierre,Ronga, Luisa,Puget, Karine,Verdie, Pascal,Amblard, Muriel,Martinez, Jean,Subra, Gilles
, p. 1395 - 1403 (2014/01/06)
Despite correct purity of crude peptides prepared on trityl resin by Fmoc/tBu microwave assisted solid phase peptide synthesis, surprisingly, lower yields than those expected were obtained while preparing C-terminal acid peptides. This could be explained
