Reaktion #1993393

Reaktionsgleichung

chromanone

rac.-[[3,4-dihydro-2-[6-[(tetrahydro-2H-pyran-2-yl)oxy]hexyl]-2-methyl-4-oxo-8-propyl-2H-1-benzopyran-7-yl]oxy]acetic acid methyl ester

→

rac.-[[3,4-dihydro-2-(6-hydroxyhexyl)-2-methyl-4-oxo-8-propyl-2H-1-benzopyran-7-yl]oxy]acetic acid methyl ester

Ausbeute 87.1%

Lösungsmittel

methanol

hydrochloric acid

Reaktionsbedingungen

Aufarbeitung

1. 1
   Einengenthen concentrated in vacuo
2. 2
   Sonstigeto remove most of the methanol
3. 3
   workup.ADDITIONThe residue was diluted with water
4. 4
   Extraktionextracted 4 times with ether
5. 5
   WaschenThe combined ether extracts were washed with water and brine
6. 6
   Trocknendried (magnesium sulfate)
7. 7
   Filtrationfiltered
8. 8
   Einengenconcentrated in vacuo in yield 1.85 g of an oil
9. 9
   SonstigeThis material was purified by HPLC (silica gel, 1.5:1 ethyl acetate-hexane)

Vorschrift

A solution of 2.3 g of the chromanone product from Example 2 in 25 ml of methanol and 5 ml of 2N hydrochloric acid was stirred for 1.75 hours at room temperature then concentrated in vacuo to remove most of the methanol. The residue was diluted with water, neutralized with sodium bicarbonate, and extracted 4 times with ether. The combined ether extracts were washed with water and brine, dried (magnesium sulfate), filtered, and concentrated in vacuo in yield 1.85 g of an oil. This material was purified by HPLC (silica gel, 1.5:1 ethyl acetate-hexane) giving 1.65 g (87.1%) of rac.-[[3,4-dihydro-2-(6-hydroxyhexyl)-2-methyl-4-oxo-8-propyl-2H-1-benzopyran-7-yl]oxy]acetic acid methyl ester as a yellow oil.

Quelle