Fmoc val

Iris Biotech (Marktredwitz, Germany): N,N-dimetylformamide (DMF), dichloromethane (DCM), trifluoroacetic acid (TFA), 2-chlorotrityl chloride resin (CTC), 4-methylbenzhydryl bromide resin (Br-MBH), and Oxyma-B. Merck KGaA (Darmstadt, Germany): Acetonitrile (MeCN) for mass spectrometry (MS) (>99.9%), TFA for MS (>99.9%), diisopropyl ether, ammonium iodide, triisopropylsilane (TIS), isopropylamine (IPA), tosyl chloride, tetrabutylammonium hydroxide (TBA-OH), ethanedithiol (EDT), diisopropylethylamine (DIPEA), and hexafluoroisopropanol (HFIP). Carbosynth (San Diego, CA, USA): Ethyl (hydroxyimino) cyanoacetate (OxymaPure) and N,N′-diisopropylcarbodiimide (DIC). GL Biochem (Shanghai, China): Fmoc-Ala-OH (Fmoc, fluorenyl-9-methyloxycarbonyl), Fmoc-Ser(tBu)-OH, Fmoc-Gln(Trt)-OH, Fmoc-Gly-OH, Boc-His(Trt)-OH, Fmoc-Phe-OH, Fmoc-Nal-OH, Fmoc-Asn(Trt)-OH, Fmoc-Met-OH, Fmoc-Leu-OH, Fmoc-Trp(Boc)-OH, Fmoc-Val-OH, Fmoc-Asp(tBu)-OH, Fmoc-Arg(Pbf)-OH, Fmoc-L-Asp(OtBu)-L-Ser[psi(Me,Me)pro]-OH, Fmoc-Tyr(tBu)-OH, Fmoc-Lys(Boc)-OH, and Fmoc-Thr(tBu)-OH.

N^α-Fmoc-protected amino acids, Fmoc-Phe, Fmoc-Val, Fmoc-Pro and Fmoc-DPro, Fmoc-Trp(Boc) and Fmoc-DTrp(Boc), Fmoc-Ser(tBu), Fmoc-Lys(Boc) and Fmoc-DLys(Boc), Fmoc-Leu and Fmoc-DLeu, Fmoc-Gly, Fmoc-Arg(Pbf), Fmoc-Nle and Fmoc-DNle, all were purchased from GL Biochem Ltd. (Shanghai, China). Other unconventional N^α-Fmoc-amino acids, namely Fmoc-Hyp(tBu) and Fmoc-DHyp(tBu), were purchased from Sigma-Aldrich (St. Louis, MO, USA), and Fmoc-Aic was acquired by Chem-Impex International (Wood Dale, IL, USA). Undecanoic, Tridecanoic, Pentadecanoic and Palmitic acids were purchased from Sigma-Aldrich. Cholesterol-PEG4 was obtained by following the synthetic procedures elsewhere reported [66 (link)]. Coupling reagents such as N,N,N′,N′-tetramethyl-O-(1H-benzo-triazol-1-yl)uronium hexafluorophosphate (HBTU) and 1-hydroxybenzotriazole (HOBt), as well as the Rink amide resin used, all were commercially obtained by GL Biochem Ltd. (Shanghai, China). N,N-diisopropylethylamine (DIEA), piperidine, and tri-fluoroacetic acid (TFA) were purchased from Iris-Biotech GMBH. Peptide synthesis solvents and reagents, such as N,N-dimethylformamide (DMF), dichloromethane (DCM), diethyl ether (Et2O), water and acetonitrile (MeCN) for HPLC, were reagent grade acquired from commercial sources (Sigma-Aldrich and VWR) and used without further purification.