Acquity sqd 2 uplc ms system

Optical rotations were recorded with a JASCO P-1020 digital polarimeter. UV spectra were recorded on a 2489 detector of Waters. ECD spectra were measured on JASCO J-815 spectrometer. IR spectra were obtained on a Nicolet Nexus 470 spectrophotometer in KBr discs. NMR spectra were recorded on a Varian System 500 spectrometer, JEOL JNM-ECP 600 spectrometer, Bruker AVANCE NEO 400 spectrometer, or Bruker AVANCE III 600 spectrometer, and chemical shifts were referenced to the corresponding residual solvent signals (δ_H/C 3.31/49.00 for methanol-d₄, δ_H/C 2.50/39.52 for DMSO-d₆). HRESIMS were measured on a Q-TOF Ultima Global GAA076 LC mass spectrometer. LC-MS data were obtained on a Waters ACQUITY SQD 2 UPLC/MS system with a reversed-phase C18 column (ACQUITY UPLC BEH C18, 2.1 × 50 mm, 1.7 μm) at a flow rate of 0.4 mL/min. Semipreparative HPLC was performed using a C18-PFP column (ACE C18-PFP, 10 × 250 mm, 5 μm), Phenyl column (YMC-Pack Ph, 10 × 250 mm, 5 μm), or π-NAP column (COSIMOSIL π-NAP, 10 × 250 mm, 5 μm). Analytical thin layer chromatography (TLC) was carried out on plates pre-coated with silica gel GF₂₅₄ (10–40 μm). Column chromatography (CC) were performed using silica gel (200–300 mesh, Qingdao Marine Chemical Factory) and Sephadex LH-20 (Amersham Biosciences).

All starting materials were purchased from commercial sources and used without further purification, or purified according to Purification of Laboratory Chemicals (Armarego, W.L.F., Chai, C.L.L. 5^th edition). Reactions were monitored by thin-layer chromatography (TLC) using TLC silica gel coated aluminum plates 60F-254 (Merck). Metforminyn was purified using a Combiflash RF+ Teledyne Isco system. ¹H NMR spectra were recorded at 300 MHz and ¹³C NMR at 75 MHz at 298 K. Chemical shifts were reported as δ values are expressed in ppm using the residual non-deuterated solvent as internal standard and coupling constants (J) in Hz. The following abbreviations are used: s, singlet; t, triplet; td, triplet doublet. UPLC trace and electrospray mass spectrum were obtained from a Waters Acquity SQD2 UPLC-MS system. HRMS was measured with a Bruker maXis LC-QTOF.