Reacción #3995

Ecuación de reacción

2,5,9-trimethyl-11-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2,4,6,8,10-undecapentaene-1-ol

triphenylphosphine

N-bromosuccinimide

→

1-methylamino-2,5,9-trimethyl-11-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2,4,6,8,10-undecapentaene

Disolventes

THF

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.ADDITIONAfter addition
2. 2
   Otrothe cooling bath is removed
3. 3
   Otroto rise slowly to room temperature
4. 4
   ConcentraciónThe mixture is concentrated in vacuo
5. 5
   workup.ADDITIONdiluted with a mixture of ether/petroleum ether
6. 6
   workup.WAITAfter sitting in refrigerator for several hours
7. 7
   Filtraciónwhich is collected by filtration
8. 8
   ConcentraciónThe filtrate is concentrated
9. 9
   workup.DISSOLUTIONdissolved in 10 ml of dry DMF
10. 10
    workup.ADDITIONTo this solution is added 2 g of triethylamine and 0.68 g of methylamine hydrochloride
11. 11
    workup.ADDITIONpoured into 500 ml of ice-water
12. 12
    ExtracciónThe crude product is extracted into ethylacetate
13. 13
    Lavadowashed with water
14. 14
    SecadoAfter drying over magnesium sulfate
15. 15
    Otrothe solvent is removed in vacuo
16. 16
    Otroto give the crude product as an oil
17. 17
    OtroThis substance is purified on HPLC (2% ethyl acetate in hexane, silica gel column)

Procedimiento

A solution of 2,5,9-trimethyl-11-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2,4,6,8,10-undecapentaene-1-ol (3.2 g, 10 mmol) and triphenylphosphine (2.88 g, 11 mmol) in 20 ml of THF is stirred in an ice bath and 1.78 g (10 mmol) of N-bromosuccinimide is added in small portions over a period of one hour. After addition, the cooling bath is removed and the temperature of the reaction mixture is allowed to rise slowly to room temperature. The mixture is concentrated in vacuo and then diluted with a mixture of ether/petroleum ether. After sitting in refrigerator for several hours, white crystals of triphenylphosphine oxide occur, which is collected by filtration. The filtrate is concentrated and dissolved in 10 ml of dry DMF. To this solution is added 2 g of triethylamine and 0.68 g of methylamine hydrochloride. The resulting mixture is stirred at room temperature for 18 hours and poured into 500 ml of ice-water. The crude product is extracted into ethylacetate and washed with water. After drying over magnesium sulfate, the solvent is removed in vacuo to give the crude product as an oil. This substance is purified on HPLC (2% ethyl acetate in hexane, silica gel column) to give 1-methylamino-2,5,9-trimethyl-11-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2,4,6,8,10-undecapentaene.

Fuente