Reaktion #93657

Reaktionsgleichung

water

3-amino-2,5-dichlorobenzoic acid

tetrahydrofuran

borontrifluoride tetrahydrofuran

→

3-amino-2,5-dichlorobenzyl alcohol

Ausbeute 11.5%

Lösungsmittel

methylene chloride

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe solution was cooled to 8°-10° C. in an ice bath
2. 2
   Temperaturto warm up slowly to room temperature
3. 3
   TemperaturThe reaction flask was then cooled again in an ice bath
4. 4
   Waschenwashed once with NaHCO3 and twice with water
5. 5
   Trocknendried over calcium sulfate
6. 6
   SonstigeThe methylene chloride solution afforded 19.2 g of crude solid product, mp 111-121
7. 7
   SonstigeFive grams of the crude solid was recrystallized from acetonitrile

Vorschrift

Into a 1 liter three-neck flask was introduced 40 g (0.19 mole) of 3-amino-2,5-dichlorobenzoic acid and 150 ml of tetrahydrofuran. The solution was cooled to 8°-10° C. in an ice bath. A borontrifluoride-tetrahydrofuran (1M) solution (280 ml) was added dropwise over a period of 1 hr. After being stirred at 8° C. for an additional 1 hr. the solution was allowed to warm up slowly to room temperature. The reaction flask was then cooled again in an ice bath and 50 ml of water was added through a dropping funnel. The mixture was taken into 1 liter of methylene chloride and washed once with NaHCO3 and twice with water, then dried over calcium sulfate. The methylene chloride solution afforded 19.2 g of crude solid product, mp 111-121. Five grams of the crude solid was recrystallized from acetonitrile to yield 4.2 g of 3-amino-2,5-dichlorobenzyl alcohol; mp 121-127; nmr (DMSO-d6) δ 4.50 (D, 2H), 5.34 (t, 1H), 5.52 (S, 2H), 6.73 (S, 2H); ir (CHCl3) 3490, 3380, 3240, 1630 and 1598 Cm-1.

Quelle