Reacción #1350068

Ecuación de reacción

Methyl iodide

potassium hydride

N-(tert-butyloxycarbonyl)-D-methionine

citric acid

18-crown-6 ether

→

N-(tert-butyloxycarbonyl)-N-methyl-D-methionine

Disolventes

tetrahydrofuran

tetrahydrofuran

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturamaintained at ice bath temperature
2. 2
   workup.WAITwas continued for one and one quarter hours
3. 3
   workup.STIRRINGstirring
4. 4
   Temperaturawith cooling
5. 5
   OtroThe mixture was partitioned between ether and water
6. 6
   ExtracciónThe ether layer was extracted with aqueous sodium bicarbonate
7. 7
   ExtracciónThe aqueous sodium bicarbonate layer was extracted with ether
8. 8
   LavadoThe latter ether layer was washed with water
9. 9
   Otrodried

Procedimiento

A solution of N-(tert-butyloxycarbonyl)-D-methionine (20 g.) in tetrahydrofuran was added dropwise with stirring to a suspension of potassium hydride (35% in mineral oil, 27.5 g.) in tetrahydrofuran (160 ml.) containing 18-crown-6 ether (1 g.) maintained at ice bath temperature. Stirring was continued for one and one quarter hours. Methyl iodide (5 ml.) was added, stirring was continued, and the temperature was allowed to rise to room temperature during 22 hours. The pH was adjusted to 3 with aqueous citric acid (1 M) with cooling. The mixture was partitioned between ether and water. The ether layer was extracted with aqueous sodium bicarbonate. The aqueous sodium bicarbonate layer was extracted with ether. The latter ether layer was washed with water, dried and stripped of ether, affording N-(tert-butyloxycarbonyl)-N-methyl-D-methionine as a syrup (15.5 g.).

Fuente