Reaction Steps
Acetic acid (5 drops) was added to a solution of 6-(2-amino-5-formyl-phenoxy)-hexanoic acid ethyl ester (0.310 g, 1.10 mmol) and 2-(3-cyano-4,5,5-trimethyl-5H-furan-2-ylidene)-malononitrile (0.26 g, 1.33 mmol) in pyridine (10 ml). After stirring for 24 hours at room temperature, the mixture was diluted with 100 mls of water causing the formation of a dark purple precipitate which was removed by suction filtration and washed with water. The material, was found to be pure 6-{2-amino-5-[2-(4-cyano-5-dicyanomethylene-2,2-dimethyl-2,5-dihydro-furan-3-yl)-vinyl]-phenoxy}-hexanoic acid ethyl ester by NMR (0.38 g, 75%). Small crystals of this product were obtained by pouring the NMR sample (chloroform) into a small amount of acetone and allowing this solution to slowly evaporate. Mp: 164.5° C. 1H NMR (400 MHz, CDCl3) δ: 7.58 (d, 1H, J=16 Hz), 7.17 (dd, 1H, J=8 Hz, J=1.6 Hz), 7.01 (d, 1H, J=1.6 Hz), 6.77 (d, 1H, J=16 Hz), 6.72 (d, 1H, J=8 Hz), 4.70 (s, 2H), 4.16 (q, 2H, J=7.2 Hz), 4.11 (t, 2H, J=6.2 Hz), 2.38 (t, 2H, J=7.2 Hz), 1.91 (m, 2H), 1.78 (s, 6H), 1.76 (m, 2H), 1.61 (m, 2H), 1.28 (t, 3H, J=7.2 Hz). 13C NMR (400 MHz, CDCl3) δ: 176.06, 174.30, 173.59, 148.75, 146.35, 143.18, 126.97, 124.02, 113.85, 112.40, 111.65, 111.16, 110.20, 109.73, 96.99, 68.41, 60.35, 34.14, 28.78, 26.75, 25.65, 24.63, 14.26. IR (neat): 3461, 3341, 3251, 3215, 2987, 2946, 2873, 2360, 2219, 2208, 1728, 1630, 1587, 1549, 1521, 1482, 1448, 1415, 1357, 1335, 1273, 1235, 1211, 1187, 1166, 1145, 1108, 1028, 1013, 961, 946, 906, 871, 861, 828, 816, 805, 748.
