Formic Acid → Methyl (3-chloro-4-formylphenyl)acetate
Reaktionsgleichung
[CH3:1][O:2][C:3](=[O:14])[CH2:4][C:5]1[CH:10]=[CH:9][C:8]([C:11]#N)=[C:7]([Cl:13])[CH:6]=1.C(O)=[O:16]>>[CH3:1][O:2][C:3](=[O:14])[CH2:4][C:5]1[CH:10]=[CH:9][C:8]([CH:11]=[O:16])=[C:7]([Cl:13])[CH:6]=1Komponenten
3
Reaktionsbedingungen
- Temperatur
- 110 °C
Versuchsvorschrift
A solution of (3-chloro-4-cyano-phenyl)acetic acid methyl ester 13 (7.4 g, 35.3 mmol) in 88% formic acid (100 mL) is combined with Raney-alloy (9.0 g) and heated to reflux for 10 hours at 110° C. After cooling to room temperature, the alloy is removed by filtration over Celite. The filtrate is concentrated to ˜10% of the original volume and diluted with EtOAc (250 mL) and washed three times with water (80 mL). The organic layer is dried (MgSO4), filtered and concentrated to afford crude product, which is purified by silica gel chromatography using an EtOAc/hexane gradient to give (3-Chloro-4-formyl-phenyl)-acetic acid methyl ester 14 as a wax-like solid. Another amount of product 14 is collected by reesterification of saponified byproduct (3-Chloro-4-formyl-phenyl)-acetic acid: 1H-NMR (400 MHz, CDCl3) δ=10.31 (s, 1H), 7.84 (d, J=8.0 Hz, 1H), 7.58 (s, 1H), 7.45 (d, J=8.0 Hz, 1H), 3.86 (s, 3H), 3.64 (s, 2H). MS calculated for C10H10ClO3 (M+H+) 213.0, found 213.3.