Reaktion #318898

Reaktionsgleichung

tert-butyllithium

tetramethylenediamine

trifluoromethanesulfonic acid

butyllithium hexane

3-[2-bromo-1-(tert-butyldimethylsilyl)-9,10-didehydro-6-methyl-8α-ergolinyl]-1,1-diethylurea

hexamethyldisilazane

→

3-[1-(tert-butyldimetylsilyl)-9,10-didehydro-2,6-dimethyl-8α-ergolinyl]-1,1-diethylurea

Ausbeute 27.4%

Lösungsmittel

water

toluene

toluene

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.WAITis continued for another 15 minutes at 0° C
2. 2
   Temperaturthe batch is cooled to -90° C
3. 3
   workup.ADDITIONis added
4. 4
   ExtraktionExtraction
5. 5
   WaschenThe organic phases are washed with saturated sodium bicarbonate solution and water
6. 6
   TrocknenThe combined ethyl acetate phases are dried over sodium sulfate
7. 7
   Einengenconcentrated
8. 8
   SonstigeCrystallization from methanol

Vorschrift

Under argon, 0.3 ml (1.5 mmol) of distilled hexamethyldisilazane is added to 4 ml of absolute, freshly distilled toluene, and the mixture is cooled to 0° C. Then 0.85 ml (1.4 mmol) of 15% butyllithium/hexane is added dropwise and the mixture is stirred for 15 minutes at 0° C. To this mixture is added 531 mg (1 mmol) of 3-[2-bromo-1-(tert-butyldimethylsilyl)-9,10-didehydro-6-methyl-8α-ergolinyl]-1,1-diethylurea in 50 ml of absolute, freshly distilled toluene and agitation is continued for another 15 minutes at 0° C. After adding 1 ml of distilled tetramethylenediamine, the batch is cooled to -90° C. At this temperature, 5 ml (7 mmol) of 1.4M tert-butyllithium is added and the mixture is agitated for 2 minutes before 0.6 ml (5.4 mmol) of the methyl ester of trifluoromethanesulfonic acid is added thereto. After 11/2 hours of agitation at -70° C., water is added to work up the reaction mixture. Extraction is performed with ethyl acetate. The organic phases are washed with saturated sodium bicarbonate solution and water. The combined ethyl acetate phases are dried over sodium sulfate and concentrated. Crystallization from methanol produces 128 mg of 3-[1-(tert-butyldimetylsilyl)-9,10-didehydro-2,6-dimethyl-8α-ergolinyl]-1,1-diethylurea (27% yield).

Quelle