تفاعل #8586

معادلة التفاعل

triethylamine

2-(6-chloro-2-pyridinyl)-1-(4-fluorophenyl)ethanone oxime

trifluoroacetic anhydride

→

7-chloro-2-(4-fluorophenyl)pyrazolo[1.5-α]pyridine

المردود 68.3%

المذيبات

1,2-dimethoxyethane

1,2-dimethoxyethane

ظروف التفاعل

المعالجة

1. 1
   أخرىthe temperature below 10° C
2. 2
   workup.ADDITIONAfter the addition
3. 3
   درجة الحرارةThe solution was then cooled to 4° C.
4. 4
   درجة الحرارةAfter warming to room temperature
5. 5
   درجة الحرارةthe reaction was heated
6. 6
   درجة الحرارةto reflux for 3 hours
7. 7
   تركيزThe reaction was concentrated
8. 8
   أخرىthe resulting solid was recrystallized from ethyl acetate-hexanes

الإجراء التجريبي

To a solution of 2-(6-chloro-2-pyridinyl)-1-(4-fluorophenyl)ethanone oxime (109.2 g, 414 mmol) in 1,2-dimethoxyethane (500 mL) at 0° C. was added trifluoroacetic anhydride (59 mL, 414 mmol), keeping the temperature below 10° C. 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 (116 mL, 828 mmol) in 1,2-dimethoxyethane (60 mL) was added over 0.5 hours. After warming to room temperature, the mixture was stirred for 1.5 hours. To this was added iron(II) chloride (0.52 g, 4.1 mmol) and the reaction was heated to reflux for 3 hours. The reaction was concentrated and the resulting solid was recrystallized from ethyl acetate-hexanes to give 7-chloro-2-(4-fluorophenyl)pyrazolo[1.5-α]pyridine (69.7 g. 68%) as off-white needles. 1H NMR (CDCl3): δ 8.03 (m, 2 H), 7.54 (d, 1 H), 7.16 (m, 3 H), 6.93 (d, 1 H), 6.91 (s, 1 H); MS m/z 247 (M+1); mp 156–157° C.

المصدر