Reacción #81346

Ecuación de reacción

N-methylmorpholine

dicyclohexylcarbodiimide

TFA

(2S)-2-amino-3-methylbutyric acid [11β,21-dihydroxy-6α-fluoro-16α-methyl-3,20-dioxo -pregna-1,4-dien-21-yl] ester trifluoroacetate

Boc-Ala-Ala-Pro-OH

N-hydroxybenzotriazole

→

N-(N-(N-(N-((1,1-dimethyl) ethoxycarbonyl) -L-alanyl) -L-alanyl)-L-prolyl)-L-valine [6α-fluoro-11β,21-dihydroxy-16α-methyl-3,20-dioxo-pregna-1,4-dien-21-yl] ester

Rendimiento 76.0%

Disolventes

dichloromethane

dichloromethane

Condiciones de reacción

Tratamiento posterior

1. 1
   Otrofrom precipitated urea
2. 2
   Concentraciónthe filtrate is concentrated by evaporation
3. 3
   Filtraciónfiltered again

Procedimiento

884 mg (1.50 mmol) of H-Val-O-FC x TFA (Example 31), 500 mg (1.40 mmol) of Boc-Ala-Ala-Pro-OH and 168 mg (1.40 mmol) of N-hydroxybenzotriazole are dissolved in this sequence in 50 ml of dichloromethane and 330 μl (3.00 mmol) of N-methylmorpholine is added. Then, a solution of 289 mg (1.40 mmol) of dicyclohexylcarbodiimide in 2 ml of dichloromethane is added and stirred for 2 hours at room temperature. Then, it is suctioned off from precipitated urea, the filtrate is concentrated by evaporation and filtered again. Chromatography of this amount of raw material (300 g of silica gel, hexane/acetone 1:1) yields 861 mg (76%) of N-(N-(N-(N-((1,1-dimethyl) ethoxycarbonyl) -L-alanyl) -L-alanyl)-L-prolyl)-L-valine [6α-fluoro-11β,21-dihydroxy-16α-methyl-3,20-dioxo-pregna-1,4-dien-21-yl] ester. 737 mg of pure product is obtained [one or more words missing] recrystallization from dichloromethane/diisopropyl ether.

Fuente