7364-44-5Relevant academic research and scientific papers
Isolation and synthesis of falcitidin, a novel myxobacterial-derived acyltetrapeptide with activity against the malaria target falcipain-2
Somanadhan, Brinda,Kotturi, Santosh R.,Yan Leong, Chung,Glover, Robert P.,Huang, Yicun,Flotow, Horst,Buss, Antony D.,Lear, Martin J.,Butler, Mark S.
, p. 259 - 264 (2013/07/27)
A 384-well microtitre plate fluorescence cleavage assay was developed to identify inhibitors of the cysteine protease falcipain-2, an important antimalarial drug target. Bioassay-guided isolation of a MeOH extract from a myxobacterium Chitinophaga sp. Y23 isolated from soil collected in Singapore, led to the identification of a new acyltetrapeptide, falcitidin (1), which displayed an IC 50 value of 6 μM against falcipain-2. The planar structure of 1 was secured by NMR and MS/MS analysis. Attempts to isolate further material for biological testing were hampered by inconsistent production and by a low yield (100 μg l -1). The absolute configuration of 1 was determined by Marfey's analysis and the structure was confirmed through total synthesis as isovaleric acid-D-His-L-Ile-L-Val-L-Pro-NH 2. Falcitidin (1) is the first member of a new class of falcipain-2 inhibitors and, unlike other peptide-based inhibitors, does not contain reactive groups that irreversibly bind to active cysteine sites.
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.
HOBt·DCHA-mediated synthesis of sterically hindered peptides employing Fmoc-amino acid chlorides in both solution-phase and solid phase methods
Sureshbabu, Vommina V.,Sudarshan, Naremaddepalli S.,Chenna Krishna
, p. 2625 - 2637 (2008/12/22)
The synthesis of peptides employing Fmoc-amino acid chlorides in presence of HOBt·DCHA salt in solution as well as by the solid-phase methods is described. The coupling was found to be complete in 30 min and free from racemization. The synthesis of β-casomorphin by solid-phase protocol employing Fmoc-amino acid chloride/HOBt·DCHA in DMF-CH2Cl2 has also been outlined. The final peptide was obtained in 80% yield and was fully characterized. Copyright Taylor & Francis Group, LLC.
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.
Preparation, isolation, and characterization of Nα-Fmoc- peptide isocyanates: Solution synthesis of oligo-α-peptidyl ureas
Sureshbabu, Vommina V.,Patil, Basanagoud S.,Venkataramanarao, Rao
, p. 7697 - 7705 (2007/10/03)
(Chemical Equation Presented) The Nα-Fmoc-peptide isocyanates 3a-q, 4a-c, and 5a-c were prepared by the Curtius rearrangement of Nα-Fmoc-peptide acid azides in toluene under thermal, microwave, and ultrasonic conditions. All the Nsu
Synthesis of Fmoc-protected β-amino alcohols and peptidyl alcohols from Fmoc-amino acid/peptide acid azides
Babu, Vommina V. Suresh,Kantharaju,Sudarshan, Naremaddepalli S.
, p. 1880 - 1886 (2007/10/03)
An efficient synthesis of Nα-9H-fluoren-9- ylmethoxycarbony(Fmoc)-β-amino alcohols by the reduction of Fmoc-α-amino acyl azides employing aqueous NaBH4 as a reducing agent has been described. The reduction is found to be simple and almost complete. All the Fmoc-β-amino alcohols prepared are fully characterized by 1H and 13C NMR and mass spectrometry. Further, the method is extended for the reduction of seven Fmoc-dipeptidyl acids to the corresponding alcohols. Their reduction is also found to be smooth and complete.
PROCESS FOR THE PREPARATION OF VALSARTAN AND PRECURSORS THEREOF
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Page/Page column 21-23, (2008/06/13)
This invention relates to a process for preparing intermediates useful in preparing Valsartan and to a process for preparing the latter, together with synthesis intermediates of formula (IV), (V) and (VI), useful for manufacturing a medicament for the treatment of arterial hypertension or heart failure. The process for preparing Valsartan permits it to be prepared on an industrial scale with high yields and without racemisation problems, in addition to using simple and available starting products. The invention also provides a process for preparing the intermediate of formula (VI), from an intermediate of formula (V) that does not require protection of the carboxylic acid prior to N-acylation.
2,4,5-trichlorophenyl-(9H-fluoren-9-ylmethoxycarbonylamino) methylcarbamates: Synthesis, isolation, characterization and utility in the synthesis of dipeptidyl ureas
Suresh Babu, Vommina V.,Kantharaju
, p. 1046 - 1053 (2007/10/03)
An efficient synthesis of 2,4,5-trichlorophenyl-(9H-fluoren-9- ylmethoxycarbonylamino)methylcarbamates employing isocyanates derived from several Fmoc-amino acids has been described. All the carbamates made have been obtained as crystalline solids and are
Synthesis of Nα-protected peptide acids by the N→ C chain extension employing O,N-bis-trimethylsilyl-amino acids using the mixed anhydride method
Tantry, Subramanyam J.,Babu, Vommina V. Suresh
, p. 1282 - 1287 (2007/10/03)
Synthesis of Nα-protected peptide acids employing N→C extension strategy using in situ generated X-NH-CHR′-CO-O-CO- iBu and O,N-bis-trimethylsilyl-amino acids has been accomplished. The coupling is very rapid and efficient. The yield
