With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.1121-22-8,trans-Cyclohexane-1,2-diamine,as a common compound, the synthetic route is as follows.
Into a solution containing 1,6-diisocyanatohexane (4.04 grams, 24.0 mmol; obtained from Sigma-Aldrich Fine Chemicals) and anhydrous tetrahydrofuran (100 mL, obtained from Sigma-Aldrich Fine Chemicals) stirring at room temperature was added 1-octanol (3.13 grams, 24.0 mmol, obtained from Sigma-Aldrich Fine Chemicals) and dibutyltin dilaurate (0.15 grams, 0.24 mmol, obtained from Sigma-Aldrich Fine Chemicals) as the catalyst. The mixture was stirred and heated to an internal temperature of about 65 C. The progress of the reaction was monitored by 1H-NMR spectroscopy for the consumption of 1-octanol starting material, indicated by the disappearance of the -CH2OH multiplet, which appears at 3.6 ppm downfield of the intermediate isocyanate product whose signal is located at 3.35 ppm. The mixture was cooled to about 15 C. internal temperature; thereafter, to this mixture was added dropwise a solution of trans-1,2-diaminocyclohexane (1.37 grams, 12 mmol; obtained as a racemic mixture of (1R,2R) and (1S,2S) stereoisomers from Sigma-Aldrich Fine Chemicals) dissolved in anhydrous tetrahydrofuran (10 mL). The mixture was stirred for about 60 minutes while warming up to room temperature, and thickened to form a gelatinous slurry. FTIR spectroscopic analysis of a reaction sample showed very little unreacted isocyanate (peak at 2180 cm-1, sample prepared as a KBr pellet). Residual isocyanate was quenched by addition of 5 mL of methanol. A crystalline product was isolated from the slurry by first adding diethyl ether (20 mL) followed with stirring for approximately 30 minutes to ensure full precipitation out of the gel slurry. The solid was filtered by suction on a paper filter, rinsed with diethyl ether, and then dried in air to give 6.20 grams of off-white solid (77.5% yield). The product was believed to be of the formulae 1H-NMR spectroscopic analysis of the solid was performed in DMSO-d6 (300 MHz) at high temperature (60 C.) and indicated the above structure with the following assigned peaks: 0.90 ppm (multiplet, 3 H integration, -OCH2(CH2)6CH3); 1.05-1.95 ppm (broad multiplets, 24 H integration, 12 methylene protons from 2-ethylhexanol portion, 8 methylene protons from the 1,6-diisocyanatohexane portion, and 4 methylene protons from the cyclohexane ring portion); 2.95 ppm (narrow multiplet, 4 H integration, -NH(CO)NHCH2(CH2)4CH2NH(CO)O); 3.35 ppm (doublet, 1 H integration, tertiary methine proton adjacent to urea group on cyclohexane ring); 3.90 ppm (doublet of doublets, 2 H integration, NH(CO)OCH2(CH2)6CH3; 5.70 ppm and 5.85 ppm (each a broad singlet, 1 H integration, urea NH protons); 7.00 ppm (broad singlet, 1 H integration, urethane NH proton). Elemental analysis calculated for C: 64.19%, H: 10.49%, N: 11.82%; found for C: 64.46%, H: 10.63%, N: 10.69%.
1121-22-8, 1121-22-8 trans-Cyclohexane-1,2-diamine 43806, achiral-catalyst compound, is more and more widely used in various fields.
Reference£º
Patent; Xerox Corporation; US2006/122415; (2006); A1;,
Chiral Catalysts
Chiral catalysts – SlideShare