Electrothermal melting point apparatus

Sodium hydroxide (98%), 4-fluorobenzaldehyde (99%), 4-methoxybenzaldehyde (98%), thiosemicarbazide (98%), triethylamine (99%), and solvents were obtained from different sources, including Merck (Gillingham, UK) and Thermo Fisher Scientific (Waltham, MA, USA). Melting points were determined using an Electrothermal melting point apparatus (Cole-Parmer, Illinois, IL, USA. The NMR spectra (δ in ppm and J in Hz) were recorded in dimethyl sulfoxide (DMSO-d₆) using a JEOL NMR 500 MHz spectrometer (Tokyo, Japan) at 500 MHz for the ¹H and 25 MHz for the ¹³C NMR measurements. Microanalyses of carbon, hydrogen, and nitrogen were carried out using a CHNS-932 (LECO) Vario elemental analyzer. Compounds 1 [35 (link)], 3b [36 (link)], 4b [29 (link)], 6 [36 (link)], 7 [37 ], 11 [38 (link),39 (link)], and 12 [40 (link)] were prepared based on procedures in the literature.

Melting points were determined on an Electrothermal^® melting point apparatus (Cole-Parmer, Vermon Hills, IL, USA) and are uncorrected. ¹H-NMR spectra were obtained on a Mercury VX-300 spectrometer (Varian, Palo Alto, CA, USA), using deuterochloroform (CDCl₃) as the solvent. Most chemicals were purchased from Acros Organics (Fair Lawn, NJ, USA) and TCI America chemicals (Portland, OR, USA). Mass spectrometry was performed utilizing a VG Analytical 70 S magnetic sector mass spectrometer (Waters, Milford, MA, USA). Chromatography was performed using Geduran^® silica gel (40–63 µm).