Reaktion #742250

Reaktionsgleichung

3-[5-methyl-2-(tetrahydro-pyran-2-yloxy)-phenyl]-acrylic acid ethyl ester

p-toluenesulfonic acid

→

colourless crystals

Ausbeute 71.0%

(E)-3-(2-Hydroxy-5-methyl-phenyl)-acrylic acid ethyl ester

Ausbeute 71.0%

Lösungsmittel

ethanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   EinengenThen the reaction mixture was concentrated
2. 2
   workup.ADDITIONthe residue was diluted with ether
3. 3
   Waschenwashed with saturated sodium bicarbonate and brine
4. 4
   Sonstigedried
5. 5
   Sonstigeevaporated to dryness
6. 6
   SonstigeThe resulting yellow solid was recrystallized

Vorschrift

A solution of 193.7 g 3-[5-methyl-2-(tetrahydro-pyran-2-yloxy)-phenyl]-acrylic acid ethyl ester (Bunce, R., Moore, J., Org. Prep. Proc., 29(3), 293 (1997)) and 2 g p-toluenesulfonic acid in 2.5 l of ethanol was stirred at room temperature for 24 hours. Then the reaction mixture was concentrated and the residue was diluted with ether, washed with saturated sodium bicarbonate and brine, dried and evaporated to dryness. The resulting yellow solid was recrystallized to yield 97.7 g of colourless crystals.

Quelle