Reaktion #54569

Reaktionsgleichung

Water

ether

Methyl-lithium

7-hydroxy-4-(2-thienyl) dihydrocoumarin

ether

p-toluene sulphonic acid

→

phenol

2,2-Dimethyl-4-(2-thienyl)chroman-7-ol

Lösungsmittel

benzene

Reaktionsbedingungen

Aufarbeitung

1. 1
   Extraktionextracted with ether
2. 2
   Trocknenthe combined ether layers dried (MgSO4)
3. 3
   SonstigeRemoval of the solvent under reduced pressure
4. 4
   Sonstigegave a black oil which
5. 5
   TemperaturThe mixture was heated
6. 6
   Temperaturunder reflux for 3 hours in a Dean & Stark apparatus
7. 7
   SonstigeRemoval of the solvent under reduced pressure and chromatography on silica

Vorschrift

Methyl-lithium (150 ml of a 2 N solution) was added under dry N2 to a solution of 7-hydroxy-4-(2-thienyl) dihydrocoumarin (14.8 g) in dry ether (120 ml) and the mixture allowed to stand for 3 days. Water (500 ml) was added and the ether layer discarded. The aqueous layer was acidified, extracted with ether and the combined ether layers dried (MgSO4). Removal of the solvent under reduced pressure gave a black oil which was then dissolved in dry benzene (100 ml) containing a trace of p-toluene sulphonic acid. The mixture was heated under reflux for 3 hours in a Dean & Stark apparatus. Removal of the solvent under reduced pressure and chromatography on silica gave the required phenol (7 g).

Quelle