反応手順
A mixture of 1-[4-hydroxyphenyl]octan-1-one (10.0 g, 45.4 mmol), K2CO3 (9.4 g, 68.1 mmol) and iodine (1.5 g, 9.1 mmol) in acetone (100 mL), was treated with ethyl 2-bromodecanoate (13.9 g, 49.9 mmol), and the reaction was stirred at room temperature, under nitrogen, overnight. Solvent was evaporated in vacuo, and the residue partitioned between ethyl acetate and water. The organic phase was washed with saturated sodium chloride, dried over magnesium sulfate, filtered and evaporated in vacuo. The crude material was purified on a silica gel pad, eluting with 5% ethyl acetate/hexane to give ethyl (RS)-2-[4-octanoylphenoxy]decanoate (11.9 g, 62%) as a colourless oil. 1H NMR (400 MHz, CDCl3): δ 7.92 (d, J=9.0 Hz, 2H), 6.89 (d, J=9.0 Hz, 2H), 4.66 (dd, J=7.5, 5.2 Hz, 1H), 4.21 (q, J=7.0 Hz, 2H), 2.89 (t, J=7.4 Hz, 2H), 1.90-2.03 (m, 2H), 1.66-1.74 (m, 2H), 1.43-1.56 (m, 2H), 1.24-1.37 (m, 18H), 1.24 (t, J=7.2 Hz, 2H), 0.85-0.89 (m, 6H). A solution of ethyl ester (11.9 g, 28.3 mmol) in a mixture of tetrahydrofuran (360 mL), methanol (90 mL) and water (90 mL), was treated with lithium hydroxide monohydrate (5.9 g, 141.5 mmol), and the mixture was stirred at room temperature for 20 h. A second portion of lithium hydroxide monohydrate (2.3 g, 54.8 mmol) was added and the reaction was stirred at room temperature for an additional 3 h. The reaction mixture was concentrated in vacuo and the residue partitioned between ethyl acetate and water. The organic phase was washed with saturated sodium chloride, dried over magnesium sulfate, filtered and evaporated in vacuo, to give the crude product. Purification on a silica gel pad, eluting with 40% ethyl acetate/hexane; and recrystallization from hexanes gave (RS)-2-[4-octanoylphenoxy]decanoic acid (9.46 g, 86%) as a white solid. m.p. 45-47° C.; 1H NMR (400 MHz, CDCl3): δ 7.93 (d, J=9.0 Hz, 2H), 6.91 (d, J=9.0 Hz, 2H), 4.72 (dd, J=6.8, 5.7 Hz, 1H), 2.90 (t, J=7.4 Hz, 2H), 1.98-2.04 (m, 2H), 1.67-1.74 (m, 2H), 1.46-1.59 (m, 2H), 1.24-1.37 (m, 18H), 0.87 (t, J=6.9 Hz, 3H), 0.88 (t, J=6.9 Hz, 3H). A solution of the acid (9.4 g, 24.1 mmol) in ethanol (200 mL) was treated with a solution of sodium bicarbonate (2.0 g, 24.1 mmol) in water (50 mL), and the reaction was stirred at room temperature for 5 h. Solvents were concentrated in vacuo, and the solution was diluted with water (950 mL), filtered (0.2 μm), and lyophilised to give sodium (RS)-2-[4-octanoylphenoxy]decanoate as a white solid (8.8 g, 88%). mp 275-280° C.; 1H NMR (400 MHz, CD3OD): δ 7.96 (d, J =9.0 Hz, 2H), 6.97 (d, J =9.0 Hz, 2H), 4.72 (dd, J =6.2, 5.9 Hz, 1H), 2.95 (t, J =7.4 Hz, 2H), 1.94-1.99 (m, 2H), 1.64-1.72 (m, 2H), 1.49-1.57 (m, 2H), 1.28-1.40 (m, 18H), 0.90 (t, J =6.9 Hz, 3H), 0.89 (t, J=6.9 Hz, 3H); 13C NMR (101 MHz, CD3OD): δ 200.72, 177.83, 163.37, 130.20, 129.61, 114.70, 79.55, 37.94, 33.19, 31.87, 31.76, 29.45, 29.38, 29.24, 29.22, 29.16, 25.74, 24.85, 22.57, 22.52, 13.29, 13.28; LRMS (ESI): m/z 391 (M−Na++2H+); HPLC: 6 min.
