Precoated silica gel tlc plates

Synthesis of indomethacin derivatives was performed in the borosilicate glassware. REMI rota mantle and magnetic stirrers were utilized to reflux and mix the reaction mixtures. Residual solvent was recovered using a rotary vacuum evaporator (Buchi type). The melting point was estimated employing a paraffin oil bath or digital melting point apparatus (VEEGO partnership). Precoated silica gel TLC plates (MERCK) were used to monitor the reaction’s progress, and a UV chamber was utilized to detect product formation. IR spectra were recorded on JASCO FTIR by the KBr scattering process. 1H NMR and 13C NMR spectra were recorded on a BRUKER 400 MHz instrument utilizing TMS as an internal standard. Mass spectra were recorded on BRUKER utilizing ESI as a particle source.

Column chromatography was performed on A silica gel 60 (70–230 and 240–300 mesh sizes, E. Merck), Diaion HP-20 Resin and Sephadex LH-20 were used. Final purification of some compounds was achieved by preparative recycling HPLC (model LC-908) (JAI) and the columns used were L-80 or H-80 (YMC, Co. Ltd) at appropriate flow rates (4 mL/min) using equivalent combinations of MeOH and H₂O. Pre-coated silica gel TLC plates (E. Merck, F₂₅₄) were used for evaluating the compounds. TLC plates were viewed under ultraviolet light at 254 nm for fluorescence quenching spots and at 366 nm for fluorescent spots. Ceric-sulphate in 10 % H₂SO₄ spraying reagent was used for staining the compounds on TLC.