Reacción #1848933

Ecuación de reacción

water

water

N-bromosuccinimide

tetrahydro-2-[[(2Z,6E)-3,7,11-trimethyl-2,6,10-dodecatrienyl]oxy]-2H-pyran

→

(6E,10Z)-2,6,10-trimethyl-12-[(tetrahydro-2H-pyran-2-yl)oxy]-1,6,10-dodecatrien-3-ol

Disolventes

monoglyme

Condiciones de reacción

Tratamiento posterior

1. 1
   Extracciónextracted with ethyl acetate
2. 2
   LavadoThe organic phase is washed with saturated sodium chloride solution
3. 3
   OtroAfter drying
4. 4
   Otroremoving the solvent the residue
5. 5
   workup.ADDITIONcontaining tetrahydro-2-[[(2Z,6E)-10-bromo-11-hydroxy-3,7,11-trimethyl-2,6,10-dodecatrienyl]oxy]-2H-pyran
6. 6
   workup.DISSOLUTIONis dissolved in 18 ml of methanol
7. 7
   workup.ADDITIONtreated with 600 mg of potassium carbonate
8. 8
   workup.STIRRINGThe suspension is stirred at room temperature for 1.5 hours under argon
9. 9
   OtroAfter removing the methanol
10. 10
    Otroon a rotary evaporator the residue
11. 11
    workup.ADDITIONis treated 500 ml of ether and 200 ml of water
12. 12
    LavadoThe organic phase is washed with saturated sodium chloride solution
13. 13
    OtroAfter drying
14. 14
    Otroremoving the solvent the residue
15. 15
    workup.ADDITIONcontaining (6E,10Z)-2,3-epoxy-2,6,10-trimethyl-12 -[(tetrahydro-2H-pyran-2-yl)oxy]-6,10-dodecadiene
16. 16
    workup.DISSOLUTIONis dissolved in 30 ml of toluene
17. 17
    workup.ADDITIONtreated with 1.35 g of aluminum isopropylate
18. 18
    Temperaturaat reflux for 17 hours
19. 19
    Temperaturaafter cooling to room temperature
20. 20
    workup.ADDITIONpoured into 200 ml of an ice-water mixture
21. 21
    ExtracciónAfter acidification with 1N hydrochloric acid the mixture is extracted with 3×150 ml of hexane
22. 22
    LavadoThe organic phase is washed with 500 ml of saturated sodium chloride solution
23. 23
    OtroAfter drying
24. 24
    Otroremoving the solvent the residue
25. 25
    Otrois chromatographed on silica gel with a 1:2 ether-hexane mixture which additionally contains 0.1% triethylamine

Procedimiento

A solution of 2 g (0.0065 mol) of tetrahydro-2-[[(2Z,6E)-3,7,11-trimethyl-2,6,10-dodecatrienyl]oxy]-2H-pyran dissolved in 13 ml of monoglyme and 2.6 ml of water is treated portionwise at -10° with 1.3 g of N-bromosuccinimide. The mixture is subsequently stirred at 0° for 1/4 hour and at room temperature for 2 hours. The reaction solution is poured into 100 ml of water and extracted with ethyl acetate. The organic phase is washed with saturated sodium chloride solution. After drying and removing the solvent the residue, containing tetrahydro-2-[[(2Z,6E)-10-bromo-11-hydroxy-3,7,11-trimethyl-2,6,10-dodecatrienyl]oxy]-2H-pyran, is dissolved in 18 ml of methanol and treated with 600 mg of potassium carbonate. The suspension is stirred at room temperature for 1.5 hours under argon. After removing the methanol on a rotary evaporator the residue is treated 500 ml of ether and 200 ml of water. The organic phase is washed with saturated sodium chloride solution. After drying and removing the solvent the residue, containing (6E,10Z)-2,3-epoxy-2,6,10-trimethyl-12 -[(tetrahydro-2H-pyran-2-yl)oxy]-6,10-dodecadiene, is dissolved in 30 ml of toluene and treated with 1.35 g of aluminum isopropylate. The reaction mixture is boiled at reflux for 17 hours and, after cooling to room temperature, poured into 200 ml of an ice-water mixture. After acidification with 1N hydrochloric acid the mixture is extracted with 3×150 ml of hexane. The organic phase is washed with 500 ml of saturated sodium chloride solution. After drying and removing the solvent the residue is chromatographed on silica gel with a 1:2 ether-hexane mixture which additionally contains 0.1% triethylamine. There is obtained (6E,10Z)-2,6,10-trimethyl-12-[(tetrahydro-2H-pyran-2-yl)oxy]-1,6,10-dodecatrien-3-ol which has the following bands in the IR spectrum: 3445 cm-1, 1648 cm-1, 1441 cm-1, 1375 cm-1, 901 cm-1.

Fuente