反応 #64785

反応方程式

Bis(trimethylsilyl)trifluoroacetamide

L-isoleucine

2-trifluoromethyl-3-acetylthiopropionyl chloride

water

bis(trimethylsilyl)trifluoroacetamide

→

(S)-N-[2-[(acetylthio)methyl]-3,3,3-trifluoro-1-oxopropyl]-L-isoleucine

溶媒

acetonitrile

acetonitrile

methanol

反応条件

後処理

1. 1
   workup.DISSOLUTIONAt this time approximately one third of the solid had dissolved
2. 2
   workup.STIRRINGthe mixture was stirred for 45 minutes
3. 3
   温度The mixture was cooled to 0° C.
4. 4
   workup.STIRRINGAfter stirring for 18 hours at room temperature
5. 5
   抽出the resulting mixture was extracted with ethyl acetate (2×150 mL)
6. 6
   洗浄The combined organic layers were washed with brine (100 mL)
7. 7
   乾燥dried (MgSO4)
8. 8
   濃縮concentrated
9. 9
   その他to afford an oily residue which
10. 10
    その他After several chromatographies, triturations and recrystallizations 1.41 g
11. 11
    その他m.p. 81°-85° C., [α]D =-105.5° (c=0.38, methanol) were isolated

実験手順

Bis(trimethylsilyl)trifluoroacetamide (16 mL, 60 mmol.) was added to a suspension of L-isoleucine (2.62 g., 20 mmol.) in 40 mL of acetonitrile at 0° C. The suspension was allowed to warm to room temperature and stirred for 2 hours. At this time approximately one third of the solid had dissolved. An additional amount of bis(trimethylsilyl)trifluoroacetamide (4 mL, 15 mmol.) was added and the mixture was stirred for 45 minutes. The mixture was cooled to 0° C. and 2-trifluoromethyl-3-acetylthiopropionyl chloride (4.7 g., 20 mmol.) was added dropwise over 15 minutes as a solution in 10 mL of acetonitrile. After stirring for 18 hours at room temperature, the reaction mixture was a clear light yellow solution. Approximately 150 mL of water was added and the resulting mixture was extracted with ethyl acetate (2×150 mL). The combined organic layers were washed with brine (100 mL), dried (MgSO4), and concentrated to afford an oily residue which was preadsorbed onto Celite for chromatography. After several chromatographies, triturations and recrystallizations 1.41 g. of (R)-N-[2-[(acetylthio)methyl]-3,3,3-trifluoro-1-oxopropyl]-L-isoleucine; m.p. 81°-85° C., [α]D =-105.5° (c=0.38, methanol) were isolated and 1.56 g. of (S)-N-[2-[(acetylthio)methyl]-3,3,3-trifluoro-1-oxopropyl]-L-isoleucine, m.p. 111°-112° C., [α]D =+122.6° (c=0.38, methanol) were isolated.

出典