反応 #59256

反応方程式

HCl

[(2-Ethoxycarbonyl-acetyl)-(3-methyl-butyl)-hydrazono]-thiophen-2-yl-acetic acid ethyl ester

sodium ethoxide

→

desired product ( 13a )

収率 83.2%

5-Hydroxy-2-(3-methyl-butyl)-3-oxo-6-thiophen-2-yl-2,3-dihydro-pyridazine-4-carboxylic acid ethyl ester

収率 83.2%

溶媒

EtOH

反応条件

後処理

1. 1
   抽出followed by liquid-liquid extraction with H2O/EtOAc
2. 2
   洗浄The combined organic layer was washed with brine
3. 3
   乾燥dried over MgSO4
4. 4
   濃縮concentrated under reduced pressure
5. 5
   その他the residue was purified by flash chromatography on silica gel

実験手順

To a solution of [(2-Ethoxycarbonyl-acetyl)-(3-methyl-butyl)-hydrazono]-thiophen-2-yl-acetic acid ethyl ester (12a) (380 mg, 1.0 mmol) in EtOH (6 mL) at room temperature, sodium ethoxide (Aldrich) (21 wt % in ethanol, 0.4 mL, 1.1 mmol) was added, and the resulting mixture was stirred for 30 min. Aqueous HCl (5%, 0.75 mL) was added slowly, and then followed by liquid-liquid extraction with H2O/EtOAc. The combined organic layer was washed with brine, dried over MgSO4, concentrated under reduced pressure and the residue was purified by flash chromatography on silica gel to give the desired product (13a) (280 mg, 83%) as yellow solid. LC-MS (ESI+): m/e=337.30 [M+1]+(exact ms: 336.11); 1H NMR (400 MHz, CDCl3): δ 7.89 (dd, 1H, J=3.6, 1.2 Hz), 7.39 (dd, 1H, J=5.2, 1.2 Hz), 7.10 (dd, 1H, J=5.2, 3.6 Hz), 4.53 (q, 2H, J=7.2 Hz), 4.22 (m, 2H), 1.73 (m, 2H), 1.68 (m, 1H), 1.50 (t, 3H, J=7.2 Hz), 0.99 (d, 6H, J=6.4 Hz).

出典