[C:1]([O:4][C:5](=[O:7])[CH3:6])(=O)[CH3:2].[CH3:8][C:9]([CH2:13][CH2:14][CH:15]=[C:16]([CH3:34])[CH2:17][CH2:18][C:19](=[O:33])[CH:20]([CH3:32])[CH2:21][CH2:22][CH:23]=[C:24]([CH3:31])[CH2:25][CH2:26][CH:27]=[C:28]([CH3:30])[CH3:29])=CCO>N1C=CC=CC=1>[C:5]([O:4][CH2:1][CH:2]=[C:9]([CH3:8])[CH2:13][CH2:14][CH:15]=[C:16]([CH3:34])[CH2:17][CH2:18][C:19](=[O:33])[CH:20]([CH3:32])[CH2:21][CH2:22][CH:23]=[C:24]([CH3:31])[CH2:25][CH2:26][CH:27]=[C:28]([CH3:30])[CH3:29])(=[O:7])[CH3:6]To a mixture of acetic anhydride (8.1 g) and pyridine (3.2 g), 3,7,11,15,19-pentamethyl-2,6,14,18-eicosatetraen-10-on-1-ol (15 g) is added, and stirring is continued while cooling with ice for 3 hours. The reaction mixture is poured into ice water and extracted with ether. The ether extract is washed with water, dired and evaporated to give 1-acetoxy-3,7,11,15,19-pentamethyl-2,6,14,18-eicosatetraen-10-one (15 g). IR: 1740, 1710, 1675 cm-1. NMR (carbon tetrachloride): δ 1.01 (d), 1.56 (s), 1.65 (s), 1.90 (s), 1.97 (s), 2.05-2.71 (m), 4.43 (d), 4.70-5.39 (m).
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