Lc 8a preparative lc

Optical rotations were measured on a Bellingham Stanley ADP 400 Polarimeter. UV and IR readings were measured on a PerkinElmer UV-Visible spectrophotometer and a PerkinElmer spectrum 100 FT-IR spectrophotometer, respectively. ¹H, ¹³C, and 2D NMR spectra, including COSY, HSQC and HMBC, were recorded in CDCl₃ on a 400 MHz Bruker NMR spectrometer using the residual solvent signal (δ_H 7.26 and δ_C 77.4) as internal standards. Additional 1D selective NOE and NOESY spectra were obtained on a 600 MHz Bruker NMR spectrometer using the residual solvent signal (δ_H 7.26 and δ_C 77.4) as internal standards. HPLC isolation and purification of 1 was conducted on a Shimadzu LC-8A preparative LC coupled to a Shimadzu SPD-M10A VP diode array detector. Both HRESIMS data and LC-HRMS/MS analyses were obtained on a Waters Xevo G2-XS qTOF with an ESI positive ion mode and data-dependent acquisition mode. An Agilent 1100 series coupled with an Agilent LC/MSD (Liquid Chromatography/Mass Selective Detector) trap XCT mass spectrometer, equipped with an ESI interface system in negative mode, was used for the detection of the L-Marfey’s-derivatized L/D-valine, proline, N-methylphenylalanine, and alanine moieties from benderamide A.

All NMR spectra were recorded in CDCl3 on a 400 MHz Bruker NMR Spectrometer (400.13 MHz 1H, 100.61 MHz 13C) using residual solvent signals as internal references (referenced to residual CDCl3 observed at δH 7.24 or δC 77.0) with chemical shifts given in ppm downfield from TMS. Optical rotations were measured on an Anton Paar Polarimeter while UV absorbance was measured on a PerkinElmer UV-Visible spectrophotometer. The isolation and purification of compounds 1 and 2 were conducted on Shimadzu LC-8A preparative LC coupled to a Shimadzu SPD-M10A VP diode array detector HPLC.

Proton NMR spectra were recorded in CDCl₃ on a 400 MHz Bruker (Billerica, MA, USA) NMR spectrometer using the residual solvent signals (δ_H at 7.28 ppm) as internal standards. High-performance liquid chromatography isolation and purification of compound 1 was conducted on a Shimadzu (Nakagyo-ku, Kyoto, Japan) LC-8A preparative LC coupled to a Shimadzu SPD-M10A VP diode array detector. The UPLC-HRMS/MS analysis was conducted on a Waters (Milford, MA, USA) Xevo G2-XS qTOF with an ESI positive ion mode and data-dependent acquisition mode to obtain MS and MS/MS data. The HPLC-MS/MS analysis was conducted on a Thermo–Finnigan (San Jose, CA, USA) LCQ Advantage ion trap mass spectrometer with an ESI positive ion mode and data-dependent manner to obtain MS and MS/MS data. High-performance liquid chromatography preparative and analytical columns was obtained from Phenomenex (Torrance, CA, USA), and a UPLC analytical column was obtained from Waters. All solvents were HPLC-grade purchased from Thermo-Fisher Scientific (Waltham, MA, USA) and HPLC-grade water obtained by filtration using a Milli-Q Direct water purification system from Millipore (Billerica, MA, USA) unless otherwise stated. Deuterated NMR solvents were purchased from Cambridge Isotope Laboratories (Tewksbury, MA, USA).