Reaktion #1281

Reaktionsgleichung

phloroglucinol

ethyl butrylacetate

trifluoromethanesulfonic acid

→

coumarin

Ausbeute 99.1%

5,7-Dihydroxy-4-n-propylcoumarin

Ausbeute 99.1%

Lösungsmittel

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturcooled in an ice bath
2. 2
   SonstigeA drying tube was then fined to the reaction vessel
3. 3
   FiltrationAfter 30 min the solid material was collected by vacuum filtration
4. 4
   Sonstigerecrystallised from 95% ethanol

Vorschrift

A suspension of anhydrous phloroglucinol (20.0 g, 0.159 mol) in ethyl butrylacetate (26.3 g; 0.167 mol) was added over 30 min to 50 g of constantly stirred trifluoromethanesulfonic acid cooled in an ice bath. A drying tube was then fined to the reaction vessel and the mixture was stirred for 16h at 25° C., after which the resulting thick paste was combined with ice (200 g) and water (300 mL) with brisk stirring. After 30 min the solid material was collected by vacuum filtration and recrystallised from 95% ethanol to yield coumarin 15 (34.7 g; 99%) as lemon yellow crystals. mp 236°-238° C. 1H NMR (CDCl3 /CD3OD 3:1): δ6.13(1H, d; J =2.3 Hz), 6.04(1H, d; J=2.3 Hz), 5.68(1H, s), 2.76(2H, t; J=7.4 Hz), 1.47(2H, tq; J =7.7, 7.4 Hz), 0.82(3H, t; J =7.7 Hz). 13C NMR (CDCl3 /CD3OD 3:1): δ163.1, 160.7, 160.6, 157.3, 156.7, 107.8, 102.5, 99.2, 95.0, 37.7, 22.5, 13.4. Anal. calc. for C12H12O4.(H2O): C, 60.50; H, 5.92. Found: C, 60.47; H, 5.92.

Quelle