反応 #2358584

反応方程式

ethyl 3-iodo-1H-pyrazole-4-carboxylate

3,4-dihydro-2H-pyran

TsOH

→

ethyl 3-iodo-1-(oxan-2-yl)-1H-pyrazole-4-carboxylate

収率 91.4%

溶媒

THF

反応条件

後処理

1. 1
   その他quenched by the addition of 100 mL of saturated sodium bicarbonate solution
2. 2
   抽出The resulting solution was extracted with 2×80 mL of dichloromethane
3. 3
   乾燥The combined organic layers was dried over anhydrous sodium sulfate
4. 4
   濃縮concentrated under vacuum
5. 5
   その他The residue was purified on a silica gel column
6. 6
   洗浄eluted with ethyl acetate/petroleum ether (1:20)

実験手順

A solution of ethyl 3-iodo-1H-pyrazole-4-carboxylate (10.8 g, 40.60 mmol, 1.00 equiv), 3,4-dihydro-2H-pyran (10 g, 118.88 mmol, 2.93 equiv) and TsOH (780 mg, 4.53 mmol, 0.11 equiv) in THF (100 mL) was stirred for 2 h at 60° C. The reaction mixture was cooled to room temperature and quenched by the addition of 100 mL of saturated sodium bicarbonate solution. The resulting solution was extracted with 2×80 mL of dichloromethane. The combined organic layers was dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was purified on a silica gel column eluted with ethyl acetate/petroleum ether (1:20) to give 13 g (91%) of ethyl 3-iodo-1-(oxan-2-yl)-1H-pyrazole-4-carboxylate as a yellow oil. 1H NMR (400 MHz, CDCl3): δ 8.04 (s, 1H), 5.40-5.38 (m, 1H), 4.34-4.29 (m, 2H), 4.08-4.05 (m, 1H), 3.73-3.70 (m, 1H), 2.07-1.98 (m, 3H), 1.69-1.62 (m, 3H), 1.39-1.32 (m, 3H) ppm. LCMS (method C, ESI): RT=1.53 min, m/z=351.0 [M+H]+.

出典