Acetic Anhydride → 6-Bromo-8-chlorocoumarin

Temperature

136 °C

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

ORD record

ord-a5b909c104ac4124985b508e7c508547

Source dataset

uspto-grants-2002_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06372719B1