반응 #8595

반응 방정식

water

triethylamine

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

trifluoroacetic anhydride

→

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

수율 52.0%

용매

1,2-dimethoxyethane

1,2-dimethoxyethane

반응 조건

후처리

1. 1
   기타the temperature below 10° C.
2. 2
   workup.ADDITIONduring the addition
3. 3
   workup.ADDITIONAfter the addition
4. 4
   온도The solution was then cooled to 4° C.
5. 5
   온도to warm to room temperature
6. 6
   온도the reaction was heated at 75° C. for 15 hours
7. 7
   추출The resulting suspension was extracted with ethyl acetate
8. 8
   건조The organic phase was dried (magnesium sulfate)
9. 9
   여과filtered
10. 10
    농축concentrated to a solid
11. 11
    기타This solid was recrystallized from methanol

실험 절차

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).

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