反応 #2081119

反応方程式

potassium tert butoxide

pyridin-2-yl-hydrazine

but-2-ynoic acid methyl ester

→

5-methyl-1-pyridin-2-yl-1,2-dihydro-pyrazol-3-one

収率 18.7%

溶媒

tert-butanol

water

tert-butanol

反応条件

後処理

1. 1
   温度The reaction vessel was then cooled in an ice bath
2. 2
   抽出The aqueous layer was extracted once with DCM
3. 3
   ろ過the resulting precipitate was collected by filtration
4. 4
   洗浄washed with water
5. 5
   その他The solid was collected
6. 6
   乾燥dried over P2O5 in a dessicator

実験手順

To a solution of pyridin-2-yl-hydrazine (1 g) in tert-butanol (15 mL) at 30° C. was added but-2-ynoic acid methyl ester (1 g). The reaction vessel was then cooled in an ice bath was treated with potassium tert butoxide (2 g) portionwise. The resulting suspension was stirred at ambient temperature for 16 hours. The tert-butanol was reduced in vacuo and the residue was taken up in water. The aqueous layer was extracted once with DCM. The aqueous layer was then acidified with AcOH to pH=3 and the resulting precipitate was collected by filtration and washed with water. The solid was collected and dried over P2O5 in a dessicator to give 5-methyl-1-pyridin-2-yl-1,2-dihydro-pyrazol-3-one (0.3 g) as a white solid. MS (ESI+): 176.3 [M+H]+).

出典