7364-44-5Relevant articles and documents
δ13C analysis of amino acids in human hair using trimethylsilyl derivatives and gas chromatography/combustion/isotope ratio mass spectrometry
An, Yan,Schwartz, Zeland,Jackson, Glen P.
, p. 1481 - 1489 (2013/07/27)
RATIONALE To provide a simple one-step derivatization procedure for the analysis of a wide variety of amino acids in human hair by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). N,O-Bis(trimethylsilyl)trifluoroacetamide (BSTFA) derivatization is already widely used outside the IRMS community, is applicable to a variety of functional groups, and provides products that are common entries in mass spectral databases, thus simplifying compound identification. METHODS Method optimization and validation were performed on a mixture of ten standard amino acids found abundantly in human hair. The method was then applied to the analysis of scalp hair from six human subjects. The hair was washed, hydrolyzed with 6 M HCl, derivatized using BSTFA in acetonitrile and analyzed using gas chromatography (GC) with concurrent quadrupole and isotope ratio mass spectrometry (IRMS) detectors. RESULTS The reproducibility for the δ13C measurements, including the derivatization procedure and GC/C/IRMS analysis, on a day-to-day comparison was between 0.19‰ and 0.35‰ (SD, N = 12), with an average standard deviation of 0.26‰. Because trimethylsilylation adds 3N carbon atoms (where N = # reactive protons) to each amino acid, the δ13C values for amino acid derivatives were corrected using a mass balance correction and the measured kinetic isotope effect (KIE). The KIE values ranged from 0.984 to 1.020. CONCLUSIONS The procedure gave consistent δ13C values with precision similar to other derivatization methods for the range of sample sizes studied: 50-1000 μg of each amino acid. The method gave δ13C values consistent with the known literature values when applied to the analysis of amino acids in human hair. Copyright 2013 John Wiley & Sons, Ltd. Copyright
Simple and rapid synthesis of Nα-urethane protected β-amino alcohols and peptide alcohols employing HATU
Surcshbabu, Vommina V.,Sudarshan,Chennakrishnareddy
experimental part, p. 574 - 579 (2009/12/06)
The activation of the Nα--urcihanc protected (Fmoc-/Boc-/Z-/Bsmoc) α-amino acids employing l-[bis(dimethylamino)- methylene]-lH-l,2,3-triazolo-[4,5-6]pyridinium.0hexa-flurophosphate-3-oxide (HATU) followed by reduction of the in situ generated -OAt ester with NaBH 4 results in the corresponding ss-amino alcohols in good yields. This synthesis is the first demonstration of the application of the efficient coupling agent HATU for practical synthesis of ss-amino alcohols. The protocol is general for all common N-protecting groups including the highly base sensitive Bsmoc group. The protocol has also been successfully extended for the synthesis of peptide alcohols.
Pentafluorophenyl-(tert-butoxycarbonylamino) methylcarbamates: Synthesis, isolation and application to the synthesis of ureidopeptides
Sureshbabu, Vommina Venkata,Narendra,Kantharaju
, p. 920 - 926 (2008/12/23)
The one-pot synthesis of pentafluorophenyl-(tert-butoxycarbonylamino)methyl carbamates starting from N-Boc amino acids is described. Ultrasound mediated concomitant rearrangement and coupling reactions have resulted in the production of good yields of the active methyl carbamates. The carbamates have been employed as monomeric building blocks for the synthesis of dipeptidyl urea esters/acids. All the compounds obtained have been fully characterized by IR, 1H NMR, 13C NMR and mass spectroscopy.
