Reaktion #80456

Reaktionsgleichung

2-bromothiophene

2-bromothiophene

iodine

4-fluorobenzyl iodide

4-fluorobenzyl bromide

NH4Cl

I2

→

2-(4-fluorobenzyl)thiophene

Lösungsmittel

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe mixture was heated
2. 2
   Temperaturto reflux under nitrogen
3. 3
   Temperaturdropwise keeping reflux
4. 4
   workup.ADDITIONAfter the addition
5. 5
   Temperaturthe mixture was heated
6. 6
   Temperaturunder reflux for 2 h.
7. 7
   Sonstigeunder 40° C.
8. 8
   workup.STIRRINGthe mixture was stirred for 30 min.
9. 9
   Sonstigethe organic layer was separated
10. 10
    Waschenwashed with 10% sodium thiosulfate solution (50 ml)
11. 11
    workup.DISTILLATIONby distilled water (100 ml)
12. 12
    TrocknenThe organic layer was then dried over MgSO4
13. 13
    Einengenconcentrated

Vorschrift

To a suspension of Mg (3 g, 0.123 mol) in THF (40 ml) was added a small amount of solid I2 (20 mg). The mixture was heated to reflux under nitrogen. To the mixture was then added the 2-bromothiophene solution (5 ml) (19.6 g of 2-bromothiophene in 40 ml of THF). After the iodine color disappeared, to the suspension was added the rest of 2-bromothiophene solution dropwise keeping reflux. After the addition, the mixture was heated under reflux for 2 h., then was cooled to room temperature. To this mixture was added 4-fluorobenzyl iodide (or 4-fluorobenzyl bromide) followed by Li2CuCl4 (5 ml) solution keeping the temperature under 40° C. using a cool water bath. The mixture was stirred at room temperature for 2 h. To the mixture was added sat. NH4Cl solution (100 ml), the mixture was stirred for 30 min., the organic layer was separated and washed with 10% sodium thiosulfate solution (50 ml), followed by distilled water (100 ml). The organic layer was then dried over MgSO4 and concentrated to give 19 g of 2-(4-fluorobenzyl)thiophene as an oil. Purification was achieved by vacuum distillation (110° C., 5 mm Hg).

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