Reacción #1049543

Ecuación de reacción

triphenylphosphine

1-O-octadecyl-2-O- benzyl-glycerol

toluene

carbon tetrabromide

→

1-O-octadecyl-2-O-benzyl-3-bromo-1,2-propanediol

Disolventes

chloroform

Condiciones de reacción

Tratamiento posterior

1. 1
   OtroIn a 250 ml round bottom flask equipped with a magnetic stir bar
2. 2
   workup.ADDITIONTo this solution were added 4.58 g
3. 3
   FiltraciónThe yellow suspension was filtered
4. 4
   Concentraciónthe filtrate concentrated on a rotary evaporator
5. 5
   Otroto afford a white solid
6. 6
   Lavadowashed twice with 30 ml saturated sodium bicarbonate
7. 7
   Secadodried over anhydrous magnesium sulfate
8. 8
   Concentraciónconcentrated under vacuum on a rotary evaporator
9. 9
   Otroto afford 2.5 g of the crude product as a white powder
10. 10
    OtroThis crude product was purified by flash column chromatography on a silica gel 60 (E. Merck, Germany) column by sequential elution with 100 ml each of hexane, 1% ethyl acetate in hexane, 2% ethyl acetate in hexane and finally with 3% ethyl acetate in hexane
11. 11
    OtroFractions collected
12. 12
    ConcentraciónThe pooled fractions were concentrated under vacuum on a rotary evaporator

Procedimiento

In a 250 ml round bottom flask equipped with a magnetic stir bar, 2.00 g (4.6 mmoles) of 1-O-octadecyl-2-O- benzyl-glycerol (Bachem, Switzerland) was dissolved into 120 ml of toluene. To this solution were added 4.58 g. (13.8 mmoles) of carbon tetrabromide and 3.62 g. (13.8 mmoles) of triphenylphosphine and the reaction mixture stirred for 4 hours at room temperature. The yellow suspension was filtered and the filtrate concentrated on a rotary evaporator to afford a white solid. This residue was dissolved into 50 ml chloroform, washed twice with 30 ml saturated sodium bicarbonate, dried over anhydrous magnesium sulfate and concentrated under vacuum on a rotary evaporator to afford 2.5 g of the crude product as a white powder. This crude product was purified by flash column chromatography on a silica gel 60 (E. Merck, Germany) column by sequential elution with 100 ml each of hexane, 1% ethyl acetate in hexane, 2% ethyl acetate in hexane and finally with 3% ethyl acetate in hexane. Fractions collected were screened by TLC and those fractions that contained pure product (silica gel, 5% ethyl acetate in hexane, Rf=0.56) were pooled. The pooled fractions were concentrated under vacuum on a rotary evaporator to afford a quantitative yield of the 1-O-octadecyl-2-O-benzyl-3-bromo-1,2-propanediol as a white powder.

Fuente