1,3-Dibromopropane → Methyl 4-{(4E)-5-[2-(3-bromopropoxy)phenyl]-3-[4-(methoxycarbonyl)benzyl]pent-4-en-1-yl}benzoate

Participants

Reaction Conditions

Reaction Steps

0.27 g (1.35 mmol) of 1,3-dibromopropane, 29 mg (0.089 mmol) of tetrabutylammonium bromide and 0.62 g (4.5 mmol) of anhydrous potassium carbonate are added to a solution of 0.2 g (0.45 mmol) of methyl 4-{(4E)-5-(2-hydroxyphenyl)-3-[4-(methoxycarbonyl)benzyl]pent-4-en-1-yl}benzoate (racemate, Example 18A) in 4 ml of dry toluene, and the mixture is then stirred at 110° C. for a further 24 h. Another 0.27 g (1.35 mmol) of 1,3-dibromopropane are then added, and the mixture is stirred at 110° C. for a further 24 h. The mixture is then filtered through kieselguhr, and the filtrate is evaporated to dryness. The crude product obtained is purified by flash chromatography on silica gel (mobile phase: dichloromethane). This gives 0.155 g (0.274 mmol, 60.9% of theory) of a colorless oil.

Provenance & Evidence