Fmoc gly novasyn tgt

Amino-Xs were synthesized using an automated peptide synthesizer (MultiPep CF, INTAVIS Bioanalytical Instruments AG, Cologne, Germany). The synthetic protocol for glycine-conjugated peptide XG was as follows: Fmoc-protected glycine attached to a polystyrene resin (Fmoc-Gly NovaSyn TGT, Merck KGaA, Darmstadt, Germany) was deprotected by piperidine (20% in N-methylpyrrolidone (NMP). The resulting resin was reacted with 6 (99 mg, 0.14 mmol), 1-[bis(dimethylamino)methylene]-1H-benzotriazolium 3-oxide hexafluorophosphate (HBTU; 150 μL, 0.5 M in N,N-dimethylformamide (DMF), N-methylmorpholine (45 μL, 4.0 M in DMF) in NMP (8 μL) for 45 min. After washing, the N-α-protecting group of Fmoc in compound 6 was deprotected by piperidine (20% in NMP). Finally, the obtained peptide was cleaved from the resin using TFA (95% in water), yielding XG. Other peptides were synthesized using a similar method. (S)-2-amino-3-[3-bromo-4-{(2-methyl-1,1′-biphenyl-3-yl)methoxy}phenyl]propanoic acid (X) was obtained by deprotection of Fmoc in 6 using piperidine (20% in NMP).

All Fmoc-protected amino acids were purchased
from ChemPep Inc. or Iris Biotech GmbH. The following resins were
used: Fmoc-Tentgel R Ram Rink-type resin (0.18 mmol/g, Peptide International,
Fmoc-Gly-Novasyn TGT (0.2 mmol/g), Merck KGaA and Fmoc-Gly(Dmb)-Tentagel
(0.18 mmol/g), Rapp Polymere GmbH. Di-Fmoc-3,4-diaminobenzoic acid
was from AnaSpec. 2-(1H-Benzotriazole-1-yl)-1,1,3,3-tetramethyluronium
hexafluorophosphate) (HBTU) was purchased from PepChem. N,N-Dimethylformamide (DMF) was from Honeywell Burdick
& Jackson. HPLC-grade acetonitrile (MeCN) was from VWR Chemicals.
Diethyl ether was purchased from Merck KGaA. Diisopropylethylamine
(DIPEA), triisopropylsilane (TIPS), piperidine, piperazine, ethyl(hydroxyamino)
cyanoacetate (Oxyma pure), 1-hydroxybenzotriazole hydrate (HOBT),
trifluoroacetic acid (TFA), tris(2-carboxyethyl)phosphine hydrochloride
(TCEP·HCl), N-ethylmaleimide (NEM), and iodoacetamide
(IAM) were from Sigma-Aldrich. PD-10 desalting columns (Sephadex G-25
resin) for size exclusion chromatography were from GE Healthcare Bio-Sciences.