Reaktion #2005616

Reaktionsgleichung

biphenyl-carboxylic acid

3,3′,5′-Trimethyl-biphenyl-carboxylic Acid

K2CO3

→

53

Ausbeute 98.0%

1,3,8-Trimethylfluoren-9-one

Ausbeute 98.0%

Lösungsmittel

sulphuric acid

—

ice

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.WAITfor additional 1 h at ambient temperature
2. 2
   Extraktionextracted with Et2O (3×100 ml)
3. 3
   WaschenThe combined organic phases were washed with brine (75 ml)
4. 4
   Trocknendried over MgSO4
5. 5
   Filtrationfiltered
6. 6
   Sonstigethe volatiles removed in vacuo

Vorschrift

In a 250 ml 1-necked round bottom flask the biphenyl-carboxylic acid 52 (3.0 g, 12.9 mmol) was treated with concentrated sulphuric acid (40 ml) at 0° C. (ice bath). The resulting dark brown solution was stirred for 15 min at 0° C., then for additional 1 h at ambient temperature. The reaction mixture was poured in ice (100 g) whereupon the color changes to a bright yellow. The suspension was neutralized with K2CO3 and extracted with Et2O (3×100 ml). The combined organic phases were washed with brine (75 ml), dried over MgSO4, filtered and the volatiles removed in vacuo to afford 53 (2.8 g, 98%) as yellow crystals. Rf 0.52 (cyclohexane:ethylacetate 10:1). The product was used without any further purification.

Quelle