1
أخرىAcetylation of the alcohol 13 with acetic anhydride/pyridine mixture (0.1 ml/1 ml) and purification by flash chromatography
2
أخرىafforded (8Z,11Z)-8,11-tetradecadien-1-yl acetate (14) (80 mg) in 34% yield
3
أخرىas described in detail below with reference to the following reaction sequence

الإجراء التجريبي

Dry THF (3 ml) was treated with trimethylsilyl iodide (260 mg, 185 μl, 1.30 mmol) at room temperature and stirred for 15 min to form 4-trimethylsiloxybutyl iodide (11). A solution of CuCN. (LiCl)2 in THF (1M, 100 μl) was added, and the mixture was cooled to -40° C. The above prepared solution of Grignard reagent 10, was then added over a period of 30 min, and a white precipitate formed. The mixture was stirred at -40° to -20° C. for 1 hr followed by an additional 1 hr at room temperature. The reaction was quenched with ammonium chloride solution and ammonia mixture (2:1, v/v), and the product was extracted with hexane/ether (1:1) mixture (Rf =0.60, 19:1 hexane/ethyl acetate, v/v). The crude (8Z,11Z)-trimethylsiloxy-8,11-tetradecadiene (12) was dissolved in THF (6 ml) and deprotected with tetrabutylammonium fluoride solution in THF (1M, 2 ml) to form the alcohol 13. Acetylation of the alcohol 13 with acetic anhydride/pyridine mixture (0.1 ml/1 ml) and purification by flash chromatography afforded (8Z,11Z)-8,11-tetradecadien-1-yl acetate (14) (80 mg) in 34% yield based on the starting bromide (5). 1H NMR (400 MHz) δ: 5.36 (m, 4H, CH=CH-8, 9, 11, 12), 4.05 (t, J=6.7, 7.0 Hz, 2H, CH2 -1), 2.77 (dd, J=6.4, 6.4 Hz, 2H, =CH--CH2 --CH=), 2.06 (m, 4H, CH2 -7, 13), 2.04 (s, 3H, --COCH3), 1.60 (tt, J=7.3, 7.3, 7.6, 7.6 Hz, 2H, CH2 -6), 1.4-1.2 (m, 8H, CH2 -2, 3, 4, 5), 0.97 (t, J=7.3, 7.6 Hz, 3H, CH3 -14). 13C NMR (100.6 MHz) δ: 171.2 (C=O), 131.7 (=CH-12), 130.0 (=CH-11), 128.0 (=CH-9), 127.3 (=CH-8), 64.6 (CH2 -1), 29.5 (CH2 -2), 29.1 (CH2 -3, 4), 28.6 (CH2 -5), 27.2 (CH2 -6), 25.9 (CH2 -7), 25.5 (CH2 -10), 21.0 (CH3C=O), 20.5 (CH2 -13), 14.3 (CH3). MS [EI, m/z(%)] 252 (M+,2), 209 (M+ -43, 1), 192 (M+ -60, 23), 163 (4); 149 (8), 135 (14), 121 (38), 110 (19), 107 (19), 95 (39), 93 (40), 82 (26), 81 (57), 79 (66), 67 (100), 55 (38), 43 (93), 41 (50). IR (gas phase, cm-1) 3017 (cis=C--H str), 2936 (CH2), 1761 (C=O), 1233, 1040 (--O--). (3E,8Z)-3,8-tetradecadienyl acetate was synthesized as described in detail below with reference to the following reaction sequence. ##STR17##

المصدر

DOI: 10.6084/m9.figshare.5104873.v1براءة الاختراع: US05728376uspto-grants-1998_03