Synthesis, Characterization and Application Studies of 3-Methylbenzoyl Thiourea Derivatives as Organocatalysts
Two new carbonyl thiourea derivatives, 3-methyl-N-((3,3,5-trimethyl-5-((3-(3-methylbenzoyl) thioureido)methyl)cyclohexyl)carbamothioyl)benzamide (3-MBTC) and N-(3-methylbenzoyl)-N’-(4-aminobutyl)thiourea (3-MBTB) were successfully synthesized. These compounds were characterized using Fourier Transform Infra-Red, Nuclear Magnetic Resonance (1H & 13C), Micro elemental analysis, and Mass spectroscopy. The infrared spectra of these compounds showed four significant stretching vibrations, v(N-H), v(C=O), v(C-N), and v(C=S) at 3256-3235 cm-1, 1667-1663 cm-1, 1157-1152 cm-1, and 743-740 cm-1, respectively. Proton NMR spectra showed the expected resonances of (C=S-NH) and (C=O-NH) appeared in the range of δH 10.83-11.19 ppm and 11.19-11.30 ppm, respectively. Meanwhile, carbon NMR spectra showed the expected resonances of (C=O) and (C=S) appeared in δC 166-168 ppm and δC 179-180 ppm. These compounds were tested as organocatalysts in the Michael addition reaction of N-phenylmaleimide and isobutyraldehyde. The performance of the synthesized compounds as organocatalysts was monitored using Gas Chromatography-Flame Ionization Detector (GC-FID). Under optimum conditions, catalyst 3-MBTC gave 72% of yield, while 3-MBTB gave 76% of yield. Both of the synthesized compounds could act as ideal potential catalysts in Michael addition reaction.