Characterization of N<sup>α</sup>-Fmoc-protected dipeptide isomers by electrospray ionization tandem mass spectrometry (ESI-MS<sup>n</sup>): effect of protecting group on fragmentation of dipeptides
作者:M. Ramesh、B. Raju、R. Srinivas、V. V. Sureshbabu、T. M. Vishwanatha、H. P. Hemantha
DOI:10.1002/rcm.5076
日期:2011.7.30
and Y=CH(3)/H), have been characterized and differentiated by both positive and negative ion electrospray ionization ion-trap tandem massspectrometry (ESI-IT-MS(n)). In contrast to the behavior of reported unprotected dipeptide isomers which mainly produce y(1)(+) and/or a(1)(+) 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
Sodium Borohydride Reduction of Carbamoyl Azide Function: A Synthesis of<i>N</i>-Protected<i>N′</i>-Formyl-<i>gem</i>-diaminoalkyl Derivatives
作者:Giancarlo Verardo、Andrea Gorassini
DOI:10.1002/ejoc.201300442
日期:2013.8
reduction of the carbamoylazide of α-N-Boc/Fmoc/Z-protected amino acids and dipeptides (Boc = tert-butoxycarbonyl, Fmoc = 9-fluorenylmethoxycarbonyl, Z = benzyloxycarbonyl) by treatment with NaBH4 at room temperature. The reaction proceeds rapidly (45 min) without detectable epimerization (by HPLC-ESI-MS analysis) and is not influenced by the nature of the starting carbamoylazide. The 1H and 13C NMR
A facile and one-pot synthesis of Nα-Fmoc/Bsmoc/Boc/Z-protected ureidopeptides and peptidyl ureas employing diphenylphosphoryl azide [DPPA]
作者:Vommina V. Sureshbabu、G. Chennakrishnareddy、N. Narendra
DOI:10.1016/j.tetlet.2007.12.060
日期:2008.2
Diphenylphosphoryl azide (DPPA) mediated one-pot synthesis of Nα-Fmoc/Bsmoc/Boc/Z-protected ureidopeptides and peptidyl ureas as well as phenyl/succinimidyl (Nα-urethane protected) methyl carbamates starting from Nα-protected amino acids is reported. The formation of an azide, its rearrangement and coupling with an amino component is accomplished in a sequence of one-pot operations. The protocol has
direct precursors of 1,3,5-triazepan-2,6-diones, a novel class of conformationallyconstrained dipeptide mimetics. Herein, we have evaluated the use of these building blocks for the synthesis of ureido-peptides (in solution and on solid support), peptidyl hydantoins, oligoureas and some oligo(urea/amide) hybrids. Conformational investigations by NMR of ureidotripeptide 6i and pentamer 10, consisting of alternating
Sureshbabu, Vommina V.; Venkataramanarao, Rao, Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry, 2008, vol. 47, # 6, p. 910 - 919