Lc 8a pump system

Optical rotations were measured with a Rudolph Autopol IV/IV-T automatic polarimeter (NJ, USA). UV spectra were obtained on a Shimadzu UV-2600 UV-visible spectrophotometer (Shimadzu, Japan). IR spectra were recorded on a Bruker ALPHA FT-IR spectrometer (Bruker, Germany) with KBr pellets. NMR spectra were acquired on Bruker Avance 600Ⅲ spectrometers (Bruker, Germany) with tetramethylsilane as the internal standard, using methanol-d 4 or dimethyl sulfoxide-d 6 as solvents. HRESIMS experiments were conducted on a Thermo Scientific Q Exactive Quadrupole-Orbitrap mass spectrometer (Thermo, USA). Column chromatography separations were performed on polyamide (100-200 mesh, Sinopharma chemical reagent co. LTD) and silica gel (200-300 mesh, Qingdao Marine Chemical Inc., Qingdao, People's Republic of China), Sephadex LH-20 (Amersham Pharmacia Biotech, Sweden), and ODS (YMC, Japan). Analytical HPLC separations were performed with a Shimadzu LC-20AT pump system (Shimadzu, Japan) with a DAD, and semipreparative separations were performed with a Shimadzu LC-8A pump system (Shimadzu, Japan) with a DAD. Fractions were monitored by TLC (Qingdao Marine Chemical Inc., Qingdao, People's Republic of China) and visualized under a UV lamp at 254 nm and 365 nm, then detected by spraying 5% H 2 SO 4 in ethanol.

Fmoc (9-fluorenylmethyloxycarbonyl)-amino acids were obtained from Novabiochem (Merck Biosciences, La Jolla, CA). All other protected amino acids and reagents for peptide synthesis were supplied by Sigma-Aldrich (St. Louis, MO). Assembly of peptides on the Advanced ChemTech (Louisville, KY) 348-Ω peptide synthesizer was carried out on a 0.05 mmol scale by the FastMoc methodology, beginning with the H-Lol-substituted 2-chlorotrityl resin (Iris Biotech, Marktredwitz, Germany) (110 mg, loading 0.44 mmol/g). The peptide was cleaved from the resin, filtered and collected. This step was repeated three times; then, the solution was concentrated under a flow of nitrogen. The crude peptides were purified by preparative RP-HPLC on a Vydac C18 column (22 × 250 mm, 10 µ, 300 Å) using a Shimadzu (Kyoto, Japan) LC-8A pump system equipped with a SPD-6A UV-detector (flow rate 15 ml/min, λ = 216 nm) and a binary elution system: A, H