Acetic Anhydride → 6-Bromo-8-chlorocoumarin

Temperatur

136 °C

To a 5L round bottom flask fitted with a mechanical stirrer and condenser was placed 3-chloro-5-bromosalicylaldehyde (554.1 g, 2.35 mol, 1 equiv.), acetic anhydride (1203 g, 11.8 mol, 5 equiv.) and triethylamine (237.4 g, 2.35 mol, 1 equiv.). The reaction solution was heated at reflux (131-141° C.) overnight. The dark brown reaction mixture was cooled to 50° C. and ice (2 L) added (ice-bath cooling) with stirring. After one hour the mixture was filtered and the filtrate combined with EtOH (1 L). To this mixture was added EtOH (300 mL) and the reaction mixture stirred for one hour. The precipitate that formed was collected by filtration and washed with water: EtOH (3×1.3 L), vacuum and dried then dried on a fluid-bed drier. The total isolated yield is 563 g or 92%.

1. temperatureThe reaction solution was heated
2. temperatureThe dark brown reaction mixture was cooled to 50° C.
3. temperature(ice-bath cooling)
4. filtrationAfter one hour the mixture was filtered
5. additionTo this mixture was added EtOH (300 mL)
6. stirringthe reaction mixture stirred for one hour
7. customThe precipitate that formed
8. filtrationwas collected by filtration
9. washwashed with water
10. dry with materialEtOH (3×1.3 L), vacuum and dried
11. customthen dried on a fluid-bed drier
12. customThe total isolated yield is 563 g or 92%

ORD-Eintrag

ord-7a97d177746c49e491fae8f417001af7

Quelldatensatz

uspto-grants-2001_01

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US06172256B2