Reaktion #485094

Reaktionsgleichung

NaOH

5-Bromo nicotinic acid ethyl ester

sodium borohydride

HCl EtOH

HCl

→

(5-Bromo-pyridin-3-yl)-methanol Hydrochloride

Lösungsmittel

H2O

ethanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONadded portionwise over 30 min. at 20° C
2. 2
   workup.ADDITIONwas added slowly (over 20 min)
3. 3
   workup.STIRRINGthis mixture was stirred for 2 h at ambient temperature
4. 4
   SonstigeAfter evaporation of the alcohol the aqueous phase
5. 5
   Extraktionwas extracted with dichloromethane (4×150 ml)
6. 6
   Waschenthe combined extracts were washed with brine
7. 7
   Trocknenthen dried with Na2SO4
8. 8
   Filtrationfiltered
9. 9
   Sonstigeevaporated
10. 10
    workup.DISSOLUTIONThe resulting yellow oil was dissolved in a small volume of ethanol
11. 11
    Sonstigeto afford
12. 12
    Sonstigeafter removal of solvent
13. 13
    Sonstigedrying under high vacuum at 50° C. for 16 h

Vorschrift

5-Bromo nicotinic acid ethyl ester (25 g, 108 mmol) was dissolved in ethanol (500 ml) and treated with fresh sodium borohydride (25 g, 660 mmol) added portionwise over 30 min. at 20° C. Stirring was continued overnight under an argon atmosphere. Following this 1N HCl (50 ml) was added slowly (over 20 min) followed by 2N NaOH (25 ml) and H2O (75 ml) and this mixture was stirred for 2 h at ambient temperature. After evaporation of the alcohol the aqueous phase was extracted with dichloromethane (4×150 ml) and the combined extracts were washed with brine then dried with Na2SO4, filtered and evaporated. The resulting yellow oil was dissolved in a small volume of ethanol and treated with 0.93 M HCl/EtOH (62 ml, 1.2 eq.) at 4° C. over 1 h to afford, after removal of solvent and drying under high vacuum at 50° C. for 16 h, the title compound (10.9 g, 44%) as a light yellow solid. MS: m/e=186.9 (M-′).

Quelle