Reaktion #1300

Reaktionsgleichung

benzyl alcohol

KOCN

4-bromo-2-fluorobenzyl bromide

→

O-benzyl N-(4-bromo-2-fluorobenzyl)carbamate

Lösungsmittel

DMF

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigedrying tube
2. 2
   Sonstigeto the stirred reaction mixture by means of a dropping funnel
3. 3
   TemperaturThe resulting suspension is subsequently heated
4. 4
   workup.STIRRINGfurther stirred at this temperature for approximately 1.5 h
5. 5
   TemperaturThe mixture is then cooled to room temperature
6. 6
   FiltrationThe salt present in the reaction mixture is filtered off by suction via a frit
7. 7
   SonstigeThe solvent and excess benzyl alcohol are removed from the filtrate in vacuo
8. 8
   TemperaturThe light yellow oily residue is cooled with ice for crystallization
9. 9
   SonstigeThe bright crystalline mass produced
10. 10
    Waschenis washed with water
11. 11
    Filtrationfiltered
12. 12
    Sonstigedried

Vorschrift

Anhydrous and amine-free DMF (180 ml) and benzyl alcohol (28 ml) and KOCN (0.247 mol, 20 g) are charged into a 500 ml 2-neck round bottom flask having a reflux condenser and drying tube. A solution of 4-bromo-2-fluorobenzyl bromide (0.075 mol, 20 g) in DMF (20 ml) is added rapidly (in the course of 1 min) at room temperature to the stirred reaction mixture by means of a dropping funnel. The resulting suspension is subsequently heated with stirring to approximately 110° C. and further stirred at this temperature for approximately 1.5 h. The mixture is then cooled to room temperature. The salt present in the reaction mixture is filtered off by suction via a frit. The solvent and excess benzyl alcohol are removed from the filtrate in vacuo. The light yellow oily residue is cooled with ice for crystallization. The bright crystalline mass produced is washed with water, filtered and dried. Yield: 23.2 g (:91.5% of theory) M.p.: 82°-84° C. GC/MS: M+ =337, IR in KBr [cm-1 ]: 3342 (m) N--H, 1689 (s) C=O, 1535 (m) NH--C, 1276 (m) C--O--C

Quelle