Reaction Steps
A solution of methyl-2-isocyanatobenzoate (71)(1 g, 5.6 mmol) in CH2Cl2 (100 mL) was cooled to 0° C. and treated with pyridine (7 mL, 84 mmol). Cinnamyl alcohol (2.25 g, 1.68 mmol) in CH2Cl2 (150 mL) was added dropwise to the stirring solution over a period of 1 hour and the reaction mixture was allowed to stir for 12 hours, under nitrogen. The reaction mixture was washed in brine (100 mL). The aqueous phase was washed with CH2Cl2 (3×100 mL). The organic phases were combined and washed with 1N HCl (200 mL) and dried over MgSO4. Purification was achieved through flash column chromatography (80% Pet ether:EtOAc) to furnish the carbamate (72) as a colourless solid (85%). 1H NMR (250 MHz, CDCl3) δ 10.9 (br, s, 1H, NH), 8.45 (dd. 1H, J=1.0, 8.5 Hz, aromatic H), 8.01 (dd, 1H, J=1.66, 8.0 Hz, aromatic H), 7.54 (ddd, 1H, J=1.67, 7.3, 8.5 Hz, aromatic H), 7.5-7.2 (m, 5H, coc aromatic H), 7.03 (ddd, 1H, J=1.2, 8.0 Hz, aromatic H), 6.71 (d, 1H, J=16 Hz, 3′-H), 6.35 (dt, 1H, J=6.3, 16 Hz, 2′-H), 4.48 (dd, 2H, J=1.3, 6.3, 1′-H), 3.91 (s, 1H); 13C NMR (62.9 MHz, CDCl3) δ 169.0 (ester carbonyl), 153.5 (CO-carbamate), 141.9 (aromatic quat), 136.8 (aromatic quat), 135.0 (methine), 131.3 (methine), 129.0 (methine), 128.4 (methine), 127.1 (methine), 123.9 (alkenic methine), 122.0 (methine), 119.3 (methine). 114.8 (aromatic quat), 66.1 (methylene-Coc), 57.7 (OCH3). IR (neat) ν 3295, 3116, 3025, 2957, 2242, 1956, 1927, 1814, 1732, 1697, 1592, 1532, 1450, 1305, 1245, 1165, 1090, 1038, 976, 913, 856, 836, 819, 766, 743, 692 cm−1; MS m/z 311 (M+. +1), 268, 212, 188, 152, 117.
