反应详情

A mixture of 0.154 g (0.8 mmol) of 6-hydroxy-7-propyl-2H-benzofuran-3-one, 0.27 g (0.82 mmol) of 2-[(5-bromopentyl)oxy]benzenepropanoic acid methyl ester, 0.382 g (2.77 mmol) of anhydrous granular potassium carbonate, and 6 mL of anhydrous N,N-dimethylformamide was stirred at 60°-65° C. for 3 hr. The resulting slurry was cooled and the solvent was removed in vacuo. The residue was purified by flash chromatography on silica gel, eluting with 7:3 and 6:4 hexane-ethyl acetate. There was obtained 0.24 g (68%) of 2-[5-[(2,3-dihydro-3-oxo-7-propylbenzofuran-6-yl)oxy]pentyloxy]benzenepropanoic acid methyl ester as a pale-yellow oil. A 0.1 g (0.227 mmol) sample of this material was dissolved in 10 mL of tetrahydrofuran and 1 mL of 3N aqueous HCl was added. The mixture was stirred at room temperature for 2.5 hr then heated at 60°-65° C. for 28 hr. After being stirred overnight at room temperature, the solution was diluted with water and worked-up with dichloromethane in the usual manner giving a viscous oil. Flash chromatography on silica gel, eluting with ethyl acetate and 9:1 ethyl acetate-methanol gave 0.04 g (41.5%) of 2-[ 5-[(2,3-dihydro-3-oxo-7-propylbenzofuran-6-yl)oxy]pentyloxy]benzenepropanoic acid as a pale-yellow gum which crystallized. Trituration of a sample with ether-hexane gave a pale-yellow solid, mp 101°-102.5° C.

1. temperatureThe resulting slurry was cooled
2. customthe solvent was removed in vacuo
3. customThe residue was purified by flash chromatography on silica gel
4. washeluting with 7:3 and 6:4 hexane-ethyl acetate