Enantioselective Syntheses of α-Fmoc-Pbf-[2-¹³C]-l-arginine and Fmoc-[1,3-¹³C₂]-l-proline and Incorporation into the Neurotensin Receptor 1 Ligand, NT₈₋₁₃

Abstract

Enantioselective syntheses of selectively labeled, orthogonally protected [2-(13)C]-L-arginine and [1,3-(13)C(2)]-L-proline are described from the commercially available precursors [2-(13)C]bromoacetic acid and potassium [(13)C]cyanide. Interestingly the enhanced signal assigned to C-2 in the (13)C NMR spectrum of alpha-Fmoc-Pbf-[2-(13)C]-L-arginine was very broad at room temperature. The two Fmoc-labeled amino acids were used to prepare [2-(13)C]-Arg9 and [1,3-(13)C(2)]-Pro10 labeled ligand (NT(8-13)) by manual Fmoc-SPSS.

Biosynthesis of isoxazolin-5-one and 3-nitropropanoic acid containing glucosides in juvenile Chrysomelina

“…Modified literature protocols were used to synthesize [1′,2′,3′,4′,5′,6′-13 C 6 ]-2-(β-D-glucopyranosyl)-3-isoxazolin-5-one [1′,2′,3′,4′,5′,6′-13 C 6 ]-1, 37 [1′,2′,3′,4′,5′,6′- 13 18,40 and [1-13 C 15 N]-3-(hydroxyimino)propanoate (4). 39 The details of the synthetic protocols as well as the analytical data are presented in the ESI (S5-S16).…”

“…Modified literature protocols were used to synthesize [1′,2′,3′,4′,5′,6′- 13 38 2,2,2-trichloroethyl-3-nitropropanoate ( 6), 38 isoxazolin-5-(2H)-one (5), 39 [1-13 C 15 N]-3-(hydroxyamino)propanoate (3) 18,40 and [1-13 C 15 N]-3-(hydroxyimino)propanoate (4). 39 The details of the synthetic protocols as well as the analytical data are presented in the ESI (S5-S16).…”

G-protein-coupled receptor structure, ligand binding and activation as studied by solid-state NMR spectroscopy

“…It requires solid-phase peptide synthesis or chemical synthesis. This approach has been used extensively to study amyloid peptides, membrane peptides and GPCR ligand conformation [46,64,[147][148][149][150][151]. Selective labelling, including forward and reverse labelling, refers to the biosynthetic incorporation of a single type or several types of labelled amino acid(s) with the rest unlabelled into the protein expression media.…”

The chemistry and biology of organic guanidine derivatives

“…Synthetic guanidines are also extremely versatile as catalysts, as components of ionic liquids, [110][111][112][113][114][115][116][117][118][119][120] in nucleotide mimetics, [121][122][123][124][125][126] in peptide mimetics, [127][128][129][130][131][132][133][134][135][136][137] as counter-ions in anion receptor chemistry, [138][139][140][141][142][143][144][145][146][147][148][149][150][151] as super-bases, [152][153][154] as molecular transporters, [155][156][157][158]…”