Reaction Steps
2-(4'-methoxyphenyl)-6-methoxybenzo[b]thiophene 5 was prepared according to the procedure of Kost et al. To a well-stirred solution of 5 (0.500 g, 1.85 mmol) and 3,4,5-trimethoxybenzoyl chloride (0.640 g, 2.77 mmol) in CH2Cl2 (20 ml), was added AlCl3 (0.123 g, 0.925 mmol) portion-wise over a 15 minute period. After 5 hours (total reaction time), water was added, and the product was isolated initially by extraction with CH2Cl2 and subsequently by extraction with ethyl acetate (EtOAc). The organic layers were separately washed with brine and then combined and dried over MgSO4. Purification by flash chromatography (silica gel, 60:40 EtOAc/hexane) afforded 3-(3',4',5'-trimethoxybenzoyl)-2-(4'-methoxyphenyl)-6-methoxybenzo [b]thiophene (0.537 g, 1.16 mmol, 63%) as an off-white solid. Recrystallization (hexane/ethanol) afforded a highly pure crystalline sample of the compound with mp 131°-133° C. 1H-NMR (CDCl3, 360 Mhz): δ=7.66 (d,J=8.9 Hz, 1H, ArH)7.32 (d,J=2.4 Hz, 1H, ArH), 7.31 (d,J=8.8 Hz, 2H, ArH), 7.07 (s,2H, ArH), 7.01 (dd,J=8.9,2.4 Hz, 1H, ArH), 6.75 (D,J=8.8 Hz, 2H, ArH), 3.89 (s,3H, --OCH3), 3.83 (s,3H, --OCH3), 3.74 (s,3H, --OCH3), 3.73 (s, 6H, --OCH3); 13C-NMR (CDCl3, 90 Mhz): δ=192.9, 159.9, 157.7, 152.7, 143.7, 142.6, 140.1, 133.9, 132.3, 130.3, 129.9, 126.1, 124.2, 114.9, 114.1, 107.5, 104.4, 60.8, 56.1, 55.6, 55.2 HRMS (EI) M+ calcd for C26H24O6S 464.1294. and Anal. Calcd for C 26H24O6S: C, 67.23; H, 5.21; S, 6.90. Found: C, 67.20; H, 5.26; S, 6.88.
