반응 #70996

반응 방정식

isocyanatotrimethylsilane

3,4-dichloropyridine

2,2,6,6-tetramethylpiperidine

n-BuLi

hexane

acetic acid

isocyanatotrimethylsilane

→

3,4-dichloropicolinamide

수율 39.0%

용매

diethyl ether

diethyl ether

water

반응 조건

후처리

1. 1
   workup.ADDITIONAfter the addition
2. 2
   기타the cooling bath was removed
3. 3
   온도to warm to room temperature over 1 h
4. 4
   workup.STIRRINGto stir overnight
5. 5
   기타the white solid that formed
6. 6
   여과was collected through filtration
7. 7
   세척washed with water
8. 8
   추출The filtrate was extracted with ethyl acetate (3×300 mL)
9. 9
   기타The solid that was collected previously
10. 10
    workup.DISSOLUTIONwas dissolved in the combined organic layers
11. 11
    세척the resulting solution was washed with brine (2×200 mL)
12. 12
    건조dried over MgSO4
13. 13
    농축concentrated in vacuo
14. 14
    기타sonicated
15. 15
    여과The remaining solid was collected through filtration
16. 16
    세척washed with minimum amount of diethyl ether

실험 절차

To a solution of 2,2,6,6-tetramethylpiperidine (31.1 g, 0.22 mol) in diethyl ether (400 mL) at 0° C. was added n-BuLi in hexane (1.6 M, 138.0 mL, 0.22 mol) via syringe over 15 min. The resulting solution was stirred at 0° C. for 0.5 h and at −78° C. for 0.5 h. To this mixture was then slowly added a solution of 3,4-dichloropyridine (29.6 g, 0.20 mol) in diethyl ether (20 mL) via syringe over 15 min. The resulting mixture was stirred at −78° C. for 2 h before the addition of isocyanatotrimethylsilane (85% pure, 40.0 mL, 0.30 mol). The source for isocyanatotrimethylsilane is TCI. After the addition, the cooling bath was removed and the reaction mixture was allowed to warm to room temperature over 1 h. The reaction mixture was quenched with acetic acid (40 g, 0.67 mol) and 200 mL of water. The mixture was allowed to stir overnight and the white solid that formed was collected through filtration and washed with water. The filtrate was extracted with ethyl acetate (3×300 mL). The solid that was collected previously was dissolved in the combined organic layers, and the resulting solution was washed with brine (2×200 mL), dried over MgSO4 and concentrated in vacuo. The residue was suspended in 200 mL of diethyl ether and sonicated. The remaining solid was collected through filtration and washed with minimum amount of diethyl ether to provide 3,4-dichloropicolinamide (14.8 g, 39%).

출처