反应 #1283

反应方程式

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

溶剂

methanol

dimethylformamide

acetic acid

dimethylformamide

反应条件

后处理

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

实验过程

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).

来源