M 560

All fine chemicals were obtained from commercially available sources (Merck, Fluorochem, Molar Chemicals, VWR) and used without further purification. Dioxane was distilled from sodium benzophenone. Merck Kieselgel (230–400 mesh, 60 Å) was used for flash column chromatography. Melting points (uncorrected) were determined with a Büchi M-560. The ¹H- and ¹³C NMR spectra of all compounds were recorded in CDCl₃ or DMSO-d₆ solution in 5 mm tubes at RT, on a Bruker DRX-500 spectrometer at 500 (¹H) and 125 (¹³C) MHz, with the deuterium signal of the solvent as the lock and TMS as the internal standard. The HSQC, HMBC, COSY and NOESY spectra, which support the exact assignments the of ¹H- and ¹³C NMR signals, were obtained by using the standard Bruker pulse programs. For each compound characterized in this session the numbering of atoms used for assignment of ¹H- and ¹³C NMR signals do not correspond to IUPAC rules reflected from the given systematic names. The exact mass measurements were performed using a Q-TOF Premier mass spectrometer (Waters Corporation, 34 Maple St, Milford, MA, USA) in positive electrospray mode.

Melting points (m.p.) were determined as melting range (range between solidus and liquidus temperature) using a Büchi melting point apparatus M-560, open-end capillaries, a heating rate of 5 °C·min^–1, and are uncorrected.

Homogeneity/purity of all the products was analyzed by thin-layer chromatography (TLC) on alumina coated plates (Merck). Product samples in MeOH were loaded on TLC plates and developed in CHCl₃–MeOH (9.8:0.2, v/v). On detection of slight impurities by iodine vapor/UV light visualization, compounds were further purified by chromatography on silica gel columns (100–200 mesh size, CDH), using petroleum ether-ethyl acetate (3:2, v/v) as the eluent. Melting points were determined in open glass capillary tubes on a Buchi M-560 instrument and are uncorrected. Infrared (IR) spectra were recorded in KBr medium using a Perkin-Elmer Fourier Transform-IR spectrometer, whereas ¹H and ¹³C nuclear magnetic resonance (NMR) spectra were recorded in CDCl₃ medium on a JNM ECX-400P (JEOL, USA) spectrometer with tetramethylsilane (TMS) as internal reference. IR and NMR spectra were recorded at the Department of Chemistry, University of Delhi, India. Absorption frequencies (ν) are expressed in cm^-1, chemical shifts in ppm (δ-scale) and coupling constants (J) in Hz. Splitting patterns are described as singlet (s), doublet (d), triplet (t), quartet (q), and multiplet (m). High resolution mass spectroscopy (HRMS) data were collected with a resolution of 10,000 on a KRATOS MS50TC spectrometer and a Kratos Mach III type at the University of Leuven (KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium).

Chemicals were purchased from industrial manufacturers and, unless otherwise specified, were used without any further purification. Precoated Merck-silica gel 60F₂₅₄ plates were used for thin layer chromatography (TLC); UV cabinet was used to detect developed plates. Column chromatography was performed with 100–200 mesh silica gels. Melting points were recorded by Buchi M-560 instrument and were uncorrected. The IR spectroscopy was done with PerkinElmer 2000 FT-IR spectrometer; KBr disc were used for samples preparation. The ¹H NMR and ¹³C spectra were recorded on a Jeol alpha-400 and at 100.6 MHz, respectively, using TMS as an internal standard. The chemical shift values were on δ scale and the coupling constants (J) were in Hz. Signals from OH groups in ¹HNMR spectra were verified by removing them by shaking in D₂O.
High Resolution Mass Spectrometry (HRMS) was performed by AB SCIEX Triple TOFTM 5600+ equipped with Turboion Spray (TIS), SCIEX ExionLC, and PDA detector. Compounds were separated through C-18 column (2.7 µm, 4.6 × 100 mm) by eluting with methanol and water (98:2, v/v) at 0.3 ml/min at 40°C.
ED₅₀ values were estimated with the SPSS statistical package. The whole computational work was carried out by using VLifeMDS QSAR plus 4.6 software using the Lenovo PC having window 8.1 operating system and Intel (R) Celeron (R) processor.