反応 #62748

反応方程式

acetic acid

bromocresol green

sodium cyanoborohydride

acetic acid

acetic acid

ethyl 2-cyano-3-(7,8-dimethoxy-2H-1-benzopyran-5-yl)propenoate

→

Ethyl 2-cyano-3-(7,8-dimethoxy-2H-1-benzopyran-5-yl)propanoate

溶媒

ethanol

ethanol

反応条件

後処理

1. 1
   温度Heating
2. 2
   その他the ethanol removed under reduced pressure
3. 3
   抽出successively extracted with water (125 mL), saturated sodium bicarbonate (3×100 mL) and water (100 mL)
4. 4
   乾燥dried over magnesium sulfate
5. 5
   その他The volatiles were removed under reduced pressure
6. 6
   その他to leave an amber oil, 18.22 g (91.4%) which
7. 7
   その他was used without further purification

実験手順

A mixture of ethyl 2-cyano-3-(7,8-dimethoxy-2H-1-benzopyran-5-yl)propenoate (19.8 g, 0.63 mole) in ethanol (500 mL) under nitrogen was treated with acetic acid (4 mL) and a trace of bromocresol green and heated to reflux. Heating was discontinued and sodium cyanoborohydride (4.4 g, 0.07 mole) in ethanol (100 mL) was co-added with additional acetic acid (11 mL). The mixture was stirred under nitrogen for 2 hr, acetic acid (10 mL) added and the ethanol removed under reduced pressure. The resultant yellow solid was taken up in ethyl acetate (250 mL) and successively extracted with water (125 mL), saturated sodium bicarbonate (3×100 mL) and water (100 mL), then dried over magnesium sulfate. The volatiles were removed under reduced pressure to leave an amber oil, 18.22 g (91.4%) which was used without further purification.

出典