Formic Acid → 4-Amino-3-bromo-2,5-difluorobenzaldehyde
Reaktionsgleichung
[NH2:1][C:2]1[C:9]([F:10])=[CH:8][C:5]([C:6]#N)=[C:4]([F:11])[C:3]=1[Br:12].C(O)=[O:14]>[Ni]>[NH2:1][C:2]1[C:9]([F:10])=[CH:8][C:5]([CH:6]=[O:14])=[C:4]([F:11])[C:3]=1[Br:12]Komponenten
4
Edukt 2
Produkt 1
Reagenzien, Katalysatoren, Lösungsmittel 1
Versuchsvorschrift
A stirred mixture of 30 g of 4-amino-3-bromo-2,5-difluorobenzonitrile, 40 g of Raney nickel and 450 mL of 95-97% HCOOH is heated at 75°-85° C. for 1 hour. The hot solution is filtered through diatomaceous earth filter and the cake washed with 2×200 ml of CH2Cl2. The total filtrate is stripped in vacuo and the residue treated with excess saturated NaHCO3 and 500 mL of CH2Cl2. Further extraction with 2×200 mL of CH2Cl2 is followed by washing the CH2Cl2 extracts with saturated NaHCO3, 2×H2O (200 mL each), drying with Na2SO4 and evaporating in vacuo to furnish 28.25 g of crude 4-amino-3-bromo-2,5-difluorobenzaldehyde. The crude product is purified by dry-column chromatography on silica gel using CH2Cl2 as eluent to give 20.15 g (66% yield), m.p. 132°-133° C., of the title compound.