反応 #1281

反応方程式

phloroglucinol

ethyl butrylacetate

trifluoromethanesulfonic acid

→

coumarin

収率 99.1%

5,7-Dihydroxy-4-n-propylcoumarin

収率 99.1%

溶媒

water

反応条件

後処理

1. 1
   温度cooled in an ice bath
2. 2
   その他A drying tube was then fined to the reaction vessel
3. 3
   ろ過After 30 min the solid material was collected by vacuum filtration
4. 4
   その他recrystallised from 95% ethanol

実験手順

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.

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