反应详情

A mixture of 0.65 g (1.44 mmol) of 2-[6-(3,4-dihydro-4-oxo-8-propyl-2H-1-benzopyran-7-yl)hexyloxy]benzenepropanoic acid methyl ester, 2 mL of 3N aqueous lithium hydroxide, and 30 mL of tetrahydrofuran was stirred at room temperature for 24 hr and then concentrated in vacuo. The residue was diluted with water and extracted 3 times with ether (the ether extracts were discarded). The aqueous alkaline solution was acidified with 3N HCl and worked-up with ether in the usual manner. The oily residue was chromatographed on silica gel. Elution with 2:1 toluene-ethyl acetate containing acetic acid afforded 0.5 g (79.3%) of 2-[6-(3,4-dihydro-4-oxo-8-propyl-2H-1-benzopyran-7-yl)hexyloxy]benzenepropanoic acid as viscous, colorless oil.

1. concentrationconcentrated in vacuo
2. additionThe residue was diluted with water
3. extractionextracted 3 times with ether (the ether extracts
4. customThe oily residue was chromatographed on silica gel
5. washElution with 2:1 toluene-ethyl acetate
6. additioncontaining acetic acid