Carbon Dioxide → HCID 86584107, compound

Participants

Reaction Steps

Carbon dioxide was added subsurface to a dichloromethane (20 mL) solution containing phenylalanine methylester hydrochloride salt (0.005 mol, 1.07 g), N-cyclohexyl-N',N',N",N"-tetraethylguanidine (0.005 mol, 1.3 g) and triethylamine (0.02 mol, 2.0 g) at -10° C. (ice and salt bath) for 30 min at a pressure of 0 psig. The reaction mixture was transferred rapidly via cannula under carbon dioxide to a pre-cooled solution of phosphorus oxychloride (0.005 mol, 0.8 g) in 20 mL dichloromethane. After stirring for 20 min at -10° C. diethylether (40 mL) was added to the reaction mixture. A white ppt. formed and was filtered off. The filtrate was concentrated in vacuo and the residue was extracted with 3×20 mL diethylether. The ether layers were concentrated and the residue distilled under vacuum (ca. 0.1-0.3 torr) collecting product, phenylalanine methyl ester isocyanate, at 91°-93° C. (0.426 g, 41.6%) of 93% purity as judged by GC. IR (neat) 2253, 1745 cm-1. 1H NMR (CDCl3) δ 7.35-7.17 (m, 5H), 4.26 (dd, 1H, Jgem =7.7, Jvic =4.7), 3.79 (s, 3H), 3.15 (dd, 2H, Jgem =13.8, Jvic =4.7), 3.01 (dd, 1H, Jgem =13.8, Jvic =7.8) ppm.

Provenance & Evidence