反応 #8595

反応方程式

water

triethylamine

2-(6-chloro-2-pyridinyl)-1-(methoxyphenyl)ethanone oxime

trifluoroacetic anhydride

→

7-chloro-2-(4-methoxyphenyl)pyrazolo[1,5-α]pyridine

収率 52.0%

溶媒

1,2-dimethoxyethane

1,2-dimethoxyethane

反応条件

後処理

1. 1
   その他the temperature below 10° C.
2. 2
   workup.ADDITIONduring the addition
3. 3
   workup.ADDITIONAfter the addition
4. 4
   温度The solution was then cooled to 4° C.
5. 5
   温度to warm to room temperature
6. 6
   温度the reaction was heated at 75° C. for 15 hours
7. 7
   抽出The resulting suspension was extracted with ethyl acetate
8. 8
   乾燥The organic phase was dried (magnesium sulfate)
9. 9
   ろ過filtered
10. 10
    濃縮concentrated to a solid
11. 11
    その他This solid was recrystallized from methanol

実験手順

To a solution of 2-(6-chloro-2-pyridinyl)-1-(methoxyphenyl)ethanone oxime (38.7 g, 140 mmol) in 1,2-dimethoxyethane (156 mL) at 0° C. was added trifluoroacetic anhydride (20 mL, 140 mmol), keeping the temperature below 10° C. during the addition. After the addition was complete, the reaction was warmed to 15° C. The solution was then cooled to 4° C. and a solution of triethylamine (39 mL, 280 mmol) in 1,2-dimethoxyethane (15 mL) was added over a period of 0.5 hours. The mixture was allowed to warm to room temperature and was stirred at room temperature for 1.5 hours. To this mixture was added iron(II) chloride (0.18 g, 1.4 mmol) and the reaction was heated at 75° C. for 15 hours. The reaction mixture was poured into water (300 mL). The resulting suspension was extracted with ethyl acetate. The organic phase was dried (magnesium sulfate), filtered and concentrated to a solid. This solid was recrystallized from methanol to give 7-chloro-2-(4-methoxyphenyl)pyrazolo[1,5-α]pyridine (18.7 g, 52%) as pale yellow needles. 1H NMR (CDCl3): δ 7.91 (d, 2H), 7.43 (d, 1H), 7.01 (t,1H), 6.95 (d, 2H). 6.81 (d,1 1H), 6.80 (s, 1H), 3.83 (s, 3 H); MS m/z 259 (M+1).

出典