Reaction #1583865

Reaction equation

3-(4-hydroxyphenyl)-4-(4-methoxyphenyl)-2H-chromen-7-ol

→

crystals

Yield 46.3%

3-(4-Hydroxyphenyl)-4-(4-methoxyphenyl)-chroman-7-ol

Yield 46.3%

Solvents

ethanol

Conditions

Workup

1. 1
   Otherfor 3 hours
2. 2
   FiltrationThe reaction was filtered through Celite
3. 3
   Otherto remove the catalyst
4. 4
   Washrinsed through with ethanol (300 ml)
5. 5
   ConcentrationThe filtrate was concentrated to ˜50 ml
6. 6
   workup.ADDITIONbefore being poured
7. 7
   Temperatureinto chilled
8. 8
   OtherA pale orange precipitate formed which
9. 9
   Otherthen formed a brown oil
10. 10
    ExtractionThe mixture was then extracted with diethyl ether
11. 11
    Washthe combined organic layers washed with water (3×1 L), brine (1×500 ml)
12. 12
    Dryingdried over anhydrous magnesium sulphate
13. 13
    Filtrationfiltered
14. 14
    OtherThe solvent was removed in vacuo
15. 15
    Otherto give red/brown oil
16. 16
    OtherThe product was recrystallised from diethyl ether (˜100 ml)
17. 17
    Otherto give brown solid which
18. 18
    Washwas rinsed with chilled diethyl ether

Procedure

3-(4-hydroxyphenyl)-4-(4-methoxyphenyl)-2H-chromen-7-ol 25.5 g (70 mmoles), 10% Pd/Al2O3 3.95 g and 200 ml of ethanol were combined in a 2-neck 500 ml round bottom flask. The reaction was hydrogenated at low pressure using standard conditions for 3 hours. The reaction was filtered through Celite to remove the catalyst, rinsed through with ethanol (300 ml). The filtrate was concentrated to ˜50 ml before being poured into chilled, stirred water (1.4 L). A pale orange precipitate formed which then formed a brown oil. The mixture was then extracted with diethyl ether, the combined organic layers washed with water (3×1 L), brine (1×500 ml), dried over anhydrous magnesium sulphate and filtered. The solvent was removed in vacuo to give red/brown oil. The product was recrystallised from diethyl ether (˜100 ml), to give brown solid which was rinsed with chilled diethyl ether to give off-white crystals 11.3 g. The 1H NMR spectrum and numbering scheme being shown below.

Source