Reaction Steps
To a solution of 6-{2-amino-5-[2-(4-cyano-5-dicyanomethylene-2,2-dimethyl-2,5-dihydro-furan-3-yl)-vinyl]-phenoxy}-hexanoic acid ethyl ester (0.33 g, 0.71 mmol), in acetic acid (6 ml) was added 5 mls of 6M HCl. The mixture was allowed to stir at room temperature for 16 hours. After being poured into 50 mls of water, it was neutralized with a solution of saturated sodium bicarbonate and extracted with ethyl acetate. Both phases of the separatory funnel remained highly colored so solid sodium chloride was added resulting in the decoloration of the aqueous layer. The organic phase was separated and dried over magnesium sulfate and rotovapped to dryness. Purification by column chromatography (60% EtOAc, 35% Hexane, 5% EtOH) provided 6-{2-amino-5-[2-(4-cyano-5-dicyanomethylene-2,2-dimethyl-2,5-dihydro-furan-3-yl)-vinyl]-phenoxy}-hexanoic acid as a shiny green solid (0.23 g, 74%). 1H NMR (400 MHz, CDCl3) δ: 7.57 (d, 1H, J=16.0 Hz), 7.17 (dd, 1H, J=8.4 Hz, J=1.6 Hz), 7.04 (d, 1H, J=1.6 Hz), 6.79 (d, 1H, J=16.0 Hz), 6.72 (d, 1H, J=8.4 Hz), 4.12 (t, 2H, J=7.2 Hz), 2.45 (t, 2H, J=6. Hz), 1.93 (m, 2H), 1.79 (m, 8H), 1.62 (m, 2H). 13C NMR (400 MHz, CDCl3) δ: 176.65, 174.34, 174.17, 148.78, 146.49, 143.21, 127.15, 124.20, 113.86, 112.45, 112.36, 111.64, 111.13, 110.16, 109.82, 97.35, 68.62, 33.27, 30.95, 29.72, 29.28, 28.75, 26.81
