Galen 3 hot stage microscope

Reagents of analytical grade were used, and solvents were dried according to standard methods [26 ]. TLC was performed to monitor chemical reactions using aluminum plates coated with silica gel 60 F₂₅₄ from Merck (Darmstadt, Germany). Column chromatographic separations were performed using silica gel 60A 70–200 µ from Carlo Erba Reagents. Melting points (M.P.) were measured using a Leica Galen III hot-stage microscope. The NMR spectra (¹H and ¹³C) were recorded on a Bruker AVANCE III-400 NMR spectrometer (at 400 and 100 MHz). Tetramethylsilane (TMS) was used as a standard internal reference to report the chemical shifts (δ). Abbreviations: s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet, bs = broad singlet. Mass spectra (ESI-MS) were obtained on a 500 MS LC Ion Trap mass spectrometer (Varian Inc., Palo Alto, CA, USA) equipped with an ESI ion source, operated in the positive ion mode. High-resolution mass spectra (HRMS) were obtained on a Bruker Impact II quadrupole mass spectrometer (Bruker Daltoniks, Billerica, MA, USA). UV-Vis spectrophotometers were used: Perkin Elmer Lambda 35 (radical scavenging, cholinesterase inhibition) and Spectramax Plus 384 (cell assays). Fluorescence measurements were performed on a microplate reader, BMG Labtech, POLARstar OPTIMA, for evaluation of Aβ₄₂ aggregation.

Reagents of analytical grade were acquired from Honeywell, Labchem, Sigma-Aldrich and Scharlab. Solvents were dried in consonance with standard methods [45 ]. TLC was performed to monitor chemical reactions using aluminium plates coated with silica gel 60 F₂₅₄ obtained from Merck. Column chromatographic separations were performed with silica gel 60A 70–200 μ obtained from Carlo Erba Reagents. Melting points (M.P.s) were measured using a Leica Galen III hot stage microscope. NMR spectra (¹H and ¹³C) were recorded on a Bruker AVANCE III-300 NMR spectrometer (at 300 and 75 MHz). Standard internal reference of tetramethylsilane (TMS) was employed to report the chemical shifts (δ). The abbreviations used are as follows: s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet. Mass spectra (ESI-MS) were captured with a 500 MS LC Ion Trap mass spectrometer (Varian Inc., Palo Alto, CA, USA) equipped with an ESI ion source, operated in the positive ion mode. High-resolution mass spectra (HRMS) were obtained on a Bruker Impact II quadrupole mass spectrometer (Bruker Daltoniks, Billerica, MA, USA).