Compact quadrupole time of flight mass spectrometer

Mechanochemical experiments were carried out in an in-house modified Makita (Jigsaw) ball mill that was equipped with reactors (diameter: 2.0 cm; height: 2.0 cm; volume of reactor: 13.2 mL). All reactors are stainless steel and equipped with stainless steel balls (diameter: 6 mm; mass: 0.90 g;). A FT-IR-Eco ATR Bruker Alpha II Spectrometer was used for the FT-IR analysis. The IR spectra were obtained by the attenuated total reflection (ATR) method. For each experiment, 16 scans were performed in the frequency range from 650 to 4000 cm⁻¹. Melting points of all the compounds were determined using a Koffler hot-stage apparatus and are uncorrected. NMR spectra were recorded on a Bruker Advance III 400 spectrometer using CDCl₃ or DMSO-d₆ as a solvent with tetramethyl silane used as internal standard. LC-MS/MS data were recorded on a Bruker Compact quadrupole time-of-flight (QToF) mass spectrometer. Raw mass spectrometry data were processed using MZmine software (version 2.38). Solvents and chemicals used were of analytical grade, which were purchased from Sigma Aldrich and used without further purification. The purity determination of the starting materials and reaction monitoring was performed by thin-layer chromatography (TLC) on Merck silica gel G F254plates.

HRESIMS spectra were recorded on a Bruker Daltonics Compact Quadrupole Time of Flight (QToF) Mass Spectrometer using an electrospray ionisation probe, using direct injection in the positive mode. A Bruker Advanced III 400 MHz (400.13 MHz; 100.62 MHz) spectrometer at 25 °C was used to record ¹H-, ¹³C-NMR, and 2D NMR spectra. All chemical shifts (δ) are given in ppm with reference to the residual solvent signal and coupling constants (J) are in Hz. Column chromatography was performed on Sephadex LH-20 and silica gel 60 (0.040–0.063 mm, Merck). TLC was performed on percolated silica gel 60 F₂₅₄ (Merck) plates developed with Hexane-CH₂Cl₂, Hexane-EtOAc, CH₂Cl₂, CH₂Cl₂-MeOH, and EtOAc-MeOH. Thin Layer Chromatography (TLC) spots were visualized under UV light (254 and 365 nm) and by spraying with 10% aqueous or methanolic H₂SO₄ followed by heating at 90 °C.