Reaktion #2008

Reaktionsgleichung

BOP

D-Homophenylalanine benzyl ester

triethylamine

3-t-butoxycarbonylamino-3-methylbutanoic acid

→

(R)-α-[(3-t-Butoxycarbonylamino-3-methyl-1-oxobutyl)amino]benzenebutanoic acid benzyl ester

Lösungsmittel

methylene chloride

methylene chloride

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeto give a slightly cloudy solution
2. 2
   workup.STIRRINGThe reaction mixture was stirred at room temperature for 24 h
3. 3
   Sonstigethen quenched
4. 4
   workup.ADDITIONby adding saturated brine (10 ml)
5. 5
   ExtraktionThe two phase system was extracted with methylene chloride (2×25 ml)
6. 6
   Trocknenthe combined methylene chloride extracts dried over magnesium sulfate powder
7. 7
   Filtrationfiltered
8. 8
   Sonstigeevaporated on a rotary evaporator under reduced pressure
9. 9
   Sonstigeto give a cloudy, colorless oil
10. 10
    Sonstigechromatographed on silica gel using an eluant
11. 11
    SonstigeThe product was isolated
12. 12
    Sonstigeafter evaporation of the volatiles as a clear oil

Vorschrift

D-Homophenylalanine benzyl ester (725 mg; 3.23 mmol) whose preparation was described in Example 7 Step B, triethylamine (750 ml; 5,38 mmol) and 3-t-butoxycarbonylamino-3-methylbutanoic acid (585 mg; 2.69 mmol) were dissolved in dry methylene chloride (10 ml) and BOP (1.19 g, 2.69 mmol) was added with stirring in small batches to give a slightly cloudy solution. The reaction mixture was stirred at room temperature for 24 h then quenched by adding saturated brine (10 ml). The two phase system was extracted with methylene chloride (2×25 ml) and the combined methylene chloride extracts dried over magnesium sulfate powder, filtered and evaporated on a rotary evaporator under reduced pressure to give a cloudy, colorless oil. This material was taken up in the minimum volume of methylene chloride and chromatographed on silica gel using an eluant composed of ethyl acetate and hexanes in the ratio 1:1 v/v. The product was isolated after evaporation of the volatiles as a clear oil. The yield was 710 mg (88.5%). FAB-MS: -calculated for C27H36N2 O5 468.3; found 469.6 (M+1).

Quelle