Reaction #2389079

Reaction equation

4-(5-bromo-6-methoxy-2-naphthyl)-4-hydroxybut-3-en-2-one

sodium acetate trihydrate

sodium acetate

sodium acetate

→

4-(6-Methoxy-2-naphthyl)butan-2-one

Solvents

methanol

water

methanol

Conditions

Workup

1. 1
   WashThe hydrogenator is washed with nitrogen in order
2. 2
   workup.ADDITIONhydrogen is introduced at the pressure of three atmospheres
3. 3
   Washthe hydrogenator is washed with nitrogen
4. 4
   Filtrationthe reaction mixture is filtered in order
5. 5
   Concentrationconcentrated under vacuum
6. 6
   workup.ADDITIONThe oily residue is treated with 150 ml of toluene and 50 ml of water
7. 7
   Otherare separated
8. 8
   Otheris evaporated under vacuum at 70° C.
9. 9
   Otherobtaining an oil that
10. 10
    workup.WAITThe solution is kept for 2 hours at 0° C.
11. 11
    Filtrationthe precipitated solid is filtered
12. 12
    Washwashed with 10 ml of methanol
13. 13
    Otherdried in oven under vacuum
14. 14
    OtherThe methanolic filtrates from crystallization
15. 15
    Washwashing
16. 16
    Concentrationare concentrated under vacuum at half volume
17. 17
    Otherso obtaining
18. 18
    Temperatureafter cooling to 0° C.
19. 19
    Otherthe crystallization of other product that
20. 20
    Otheris dried in oven under vacuum
21. 21
    Other14 Grams of product are obtained in totality with
22. 22
    Otheran overall yield equal to 79.7%

Procedure

24.72 Grams (0.077 moles) of 4-(5-bromo-6-methoxy-2-naphthyl)-4-hydroxybut-3-en-2-one, 4.57 g of anhydrous sodium acetate and 2.58 g of sodium acetate trihydrate, equivalent to 0.075 moles of sodium acetate, 2 g of a 50% suspension in water of 5% palladium on carbon, equivalent to 0.00047 moles of palladium, and 200 ml of methanol are put in a hydrogenator. The hydrogenator is washed with nitrogen in order to eliminate the oxygen and then hydrogen is introduced at the pressure of three atmospheres. The reaction temperature is kept at 40° C. for a period of time of 6 hours, then the hydrogen is let off, the hydrogenator is washed with nitrogen and the reaction mixture is filtered in order to eliminate the catalyst. The solution is brought to pH 6 with a 5% aqueous solution of sodium hydroxide and concentrated under vacuum. The oily residue is treated with 150 ml of toluene and 50 ml of water and after stirring for 15 minutes the two layers are separated. The aqueous phase is discarded while the organic phase is evaporated under vacuum at 70° C. obtaining an oil that is dissolved in 50 ml of methanol. The solution is kept for 2 hours at 0° C. and the precipitated solid is filtered, washed with 10 ml of methanol cooled to 0° C. and dried in oven under vacuum. The methanolic filtrates from crystallization and washing are concentrated under vacuum at half volume so obtaining, after cooling to 0° C., the crystallization of other product that is dried in oven under vacuum. 14 Grams of product are obtained in totality with an overall yield equal to 79.7%.

Source