反応 #1417

反応方程式

sodium hydride

1-fluoro-2-nitrobenzene

methylene chloride

N-[(1,1-dimethylethoxy)carbonyl]-L-serine

→

N-[(1,1-Dimethylethoxy)carbonyl]-O-(2-nitrophenyl)-L-serine

溶媒

methanol

dimethylformamide

acetic acid

dimethylformamide

反応条件

後処理

1. 1
   温度a cooled
2. 2
   その他was continued at 0° until the frothing
3. 3
   その他(about 2.0 hours)
4. 4
   workup.STIRRINGstirred at 0° under argon for 4.0 hours
5. 5
   抽出extracted with ethyl acetate (2×100 ml.)
6. 6
   抽出extracted with ethyl acetate (3×500 ml.)
7. 7
   洗浄the combined organic extracts were washed with brine (100 ml.)
8. 8
   乾燥dried (anhydrous sodium sulfate)
9. 9
   ろ過filtered
10. 10
    その他evaporated to dryness
11. 11
    その他dried in vacuo
12. 12
    その他The crude product mixture was chromatographed on a silica gel column (Merck)
13. 13
    洗浄eluting the column with methylene chloride:methanol:acetic acid (100:5:0.2)
14. 14
    その他to give 27.22 g

実験手順

A solution of N-[(1,1-dimethylethoxy)carbonyl]-L-serine (24.3 g., 0.118 mole) in dry dimethylformamide (25 ml.) was added dropwise over a period of 1.0 hour to a cooled (0°, ice-salt bath) suspension of 60% sodium hydride (10.1 g., 0.25 mole) in dry dimethylformamide (200 ml.) and stirring was continued at 0° until the frothing subsided (about 2.0 hours). The reaction mixture was treated dropwise with 1-fluoro-2-nitrobenzene (14.3 ml., 0.13 mole) over a period of 20 minutes, stirred at 0° under argon for 4.0 hours then poured into ice-water (750 ml.) and extracted with ethyl acetate (2×100 ml.). The aqueous phase was brought to pH 1.0 with 6N hydrochloric acid (70 ml.), extracted with ethyl acetate (3×500 ml.) and the combined organic extracts were washed with brine (100 ml.), dried (anhydrous sodium sulfate), filtered, evaporated to dryness and dried in vacuo. The crude product mixture was chromatographed on a silica gel column (Merck), eluting the column with methylene chloride:methanol:acetic acid (100:5:0.2) to give 27.22 g. of product as a thick yellow syrup; Rf =0.27 (methylene chloride:methanol:acetic acid, 100:5:0.5).

出典