Reaction #1135824

Reaction equation

Acetic acid 3-(4-hydroxy-phenyl)-8-methyl-4-oxo-chroman-7-yl ester

imidazole

→

7-Hydroxy-3-(4-hydroxy-phenyl)-8-methyl-chroman-4-one

Solvents

EtOH

Conditions

Workup

1. 1
   TemperatureThe reaction mixture was refluxed
2. 2
   Otheron a rotary evaporator
3. 3
   workup.ADDITIONpoured
4. 4
   Temperaturechilled
5. 5
   workup.DISTILLATIONdistilled water (1.9 L)
6. 6
   workup.WAITThe water crash out was left
7. 7
   workup.STIRRINGstirring in the cold room overnight
8. 8
   FiltrationThe pale pink solid was collected by suction filtration
9. 9
   OtherThe solid was dried on the freeze dryer for 3 hours (8.31 g, 59%)

Procedure

Acetic acid 3-(4-hydroxy-phenyl)-8-methyl-4-oxo-chroman-7-yl ester (18.37 g), imidazole (21.18 g, 6 equivalents) and 100% EtOH (536 ml) were added to a round bottom flask (2 L). The reaction mixture was refluxed and monitored by HPLC. The reaction was completed at 8 hours. The reaction mixture was reduced (˜130 ml) on a rotary evaporator and poured into stirred, chilled distilled water (1.9 L). The water crash out was left stirring in the cold room overnight. The pale pink solid was collected by suction filtration. 1H NMR of the solid indicated it was 7-Hydroxy-3-(4-hydroxy-phenyl)-8-methyl-chroman-4-one with >95% purity. The solid was dried on the freeze dryer for 3 hours (8.31 g, 59%).

Source