Lcms advanced spectrometer

Normal phase analytical TLC was performed using silica gel 60 F₂₅₄ precoated plates (0.20 mm) (E-Merck, Darmstadt). Silica gel GF₂₅₄ (UNICHEM^(R), India) powder was used for the preparation of self-made 0.5 mm thick preparative TLC (PTLC) plates using glass plates measuring 20 cm × 20 cm. The spot and band were viewed under UV light (254 and 360 nm). Chloroform and methanol were obtained from ReAgent Chemical Services, UK. Solvents were removed using Rota evaporator (BUCHI Rotavapor R-200, Switzerland). ¹H NMR and ¹³C-NMR spectra were recorded on a Bruker Avance DMX400 FT-NMR spectrometer (Bruker, Billerica, MA, USA). ESI-MS data was generated using a Shimadzu LCMS Advanced spectrometer (Shimadzu, Kyoto, Japan) in the positive-ion mode. Optical rotation was measured using a polarimeter (AUTOPOL®IV, Rudolph Research Analytical, USA).

Chromatographic separations were performed by analytical TLC on Silica gel 60 F254 (0.2 mm thick), Silica gel 60 (0.063–0.200 mm) for column chromatography (70–230 mesh) (Merck KGaA, Darmstadt, Germany) and solid phase separation on Isolute C₁₈ columns (10 g; IST, Hengoed, UK). Trisodium citrate was obtained from BDH Chemicals Ltd, England, Giemsa was purchased from ESJAY Chemicals, Maharashtra 401,504, India, and pure chloroquine phosphate was supplied by Ethiopian Pharmaceutical Manufacturing Factory (EPHARM, Ethiopia).
NMR spectra were recorded at 500 MHz for ¹H and 125 MHz for ¹³C on a Bruker Avance DMX400 FT-NMR spectrometer (Bruker, Billerica, Massachusetts, USA) using tetramethylsilane (TMS) as internal standard. All spectra were measured in CDCl₃, except for compound 1, which was dissolved in CD₃OD. HRMS were determined on a Shimadzu LC‐MS Advanced spectrometer (Shimadzu, Kyoto, Japan) in the positive and negative modes.