Reaktion #1993396

Reaktionsgleichung

ester

rac.-[[2-[4-(4-acetyl-3-hydroxy-2-propylphenoxy)butyl]-3,4-dihydro-4-oxo-8-propyl-2H-1-benzopyran-7-yl]oxy]acetic acid methyl ester

lithium hydroxide monohydrate

→

rac.-[[2-[4-(4-acetyl-3-hydroxy-2-propylphenoxy)butyl]-3,4-dihydro-4-oxo-8-propyl-2H-1-benzopyran-7-yl]oxy]acetic acid

Lösungsmittel

water

water tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   Extraktionextracted with ether (the ether
2. 2
   Extraktionextract
3. 3
   Extraktionextracted 3 times with ether
4. 4
   Trocknendried (magnesium sulfate)
5. 5
   Filtrationfiltered
6. 6
   Einengenconcentrated in vacuo
7. 7
   Sonstigegiving a solid residue which
8. 8
   Sonstigewas chromatographed on 12 g of silica gel
9. 9
   WaschenElution with tetrahydrofuran
10. 10
    Sonstigegave the acid which
11. 11
    Sonstigewas recrystallized from methanol

Vorschrift

A solution of 0.3 g of the ester product from Example 17 and 0.48 g of lithium hydroxide monohydrate in 10 ml of 1:1 water-tetrahydrofuran was stirred at room temperature for 24 hours then diluted with water and extracted with ether (the ether extract was discarded). The aqueous solution was acidified with 1N hydrochloric acid and extracted 3 times with ether. The ether extracts were combined, dried (magnesium sulfate), filtered and concentrated in vacuo giving a solid residue which was chromatographed on 12 g of silica gel. Elution with tetrahydrofuran gave the acid which was recrystallized from methanol yielding rac.-[[2-[4-(4-acetyl-3-hydroxy-2-propylphenoxy)butyl]-3,4-dihydro-4-oxo-8-propyl-2H-1-benzopyran-7-yl]oxy]acetic acid as an off-white solid, m.p. 163.5°-167.0° C.

Quelle