Reacción #1788281

Ecuación de reacción

NH4Cl

NaBH4

2-acetyl-2,3,5-trimethoxy-2,5-dihydrofuran

→

2-(1-hydroxyethyl)-2,3,5-trimethoxy-2,5-dihydrofuran

Rendimiento 100.0%

2,3,5-trimethoxy-2,5-dihydrofuran

Disolventes

methanol

methanol

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturamaintaining a temperature below 15° C
2. 2
   Temperaturato warm to room temperature
3. 3
   ExtracciónExtraction of the crude product
4. 4
   Concentraciónwith chloroform and concentration

Procedimiento

2-acetyl-2,3,5-trimethoxy-2,5-dihydrofuran (9.22 g,0.049 moles) was dissolved in 100 ml of methanol and cooled to 0° C. Solid NaBH4 (4.0 g, 0.105 moles) was added portion-wise over 1 hour, maintaining a temperature below 15° C. The reaction was then allowed to warm to room temperature, and 20 ml of saturated aqueous NH4Cl added. Extraction of the crude product with chloroform and concentration yielded 9.3 g of 2-(1-hydroxyethyl)-2,3,5-trimethoxy-2,5-dihydrofuran (100%) as a clear 0.1, NMR (CDCl3 +D2O,δ) 5.5 (1H, m), 5.03 (1H, M), 3.8 (4H, m), 3.58 (3H, s), 3.3 (3H, s), 1.10 (3H, t). 2(1-hydroxy ethyl)-2,3,5-trimethoxy-2,5-dihydrofuran (2.82 g, 0.015 moles) in 2 ml methanol was added to 15 ml of formic acid over 5 minutes. To the well stirred solution was then added 20 ml of water and the reaction heated to reflux for 1 hour. After cooling, the reaction was extracted with chloroform and the chloroform concentrated to yield 1.5 g maltol, which was recrystallized from methanol to yield the pure white solid, m.p. 159°-160° C. Hydrochloric acid, hydrobromic acid, p-toluene sulfonic acid and acidic ion exchange resins can be used in place of formic acid in this Example.

Fuente