Nitric Acid → 5-Chloro-4-nitrothiophene-2-carbaldehyde
Reaktionsgleichung
[Cl:1][C:2]1[S:6][C:5]([CH:7]=[O:8])=[CH:4][CH:3]=1.[N+:9]([O-])([OH:11])=[O:10]>>[Cl:1][C:2]1[S:6][C:5]([CH:7]=[O:8])=[CH:4][C:3]=1[N+:9]([O-:11])=[O:10]Komponenten
3
Reaktionsbedingungen
- Temperatur
- -5 °C
Versuchsvorschrift
5-Chlorothiophene-2-carbaldehyde (2.0 g, 13.6 mmol) was added dropwise to a stirred fuming nitric acid (13 mL) cooled to −5° C. with an ice/methanol bath. When addition was complete the stirred reaction mixture was allowed to warm slowly to 5° C. over 1 hour, then it was poured into ice/water (200 mL). The precipitated solid was collected by filtration, dissolved in dichloromethane (100 mL), washed with water and the organic layer was separated and dried (MgSO4). After filtration the solvent was removed under reduced pressure and the residual brown solid was crystallised from hexane (insoluble brown material was removed by decantation of the supernatant solution), to afford title product as an off-white solid (1.51 g, 58%). 1H NMR (300 MHz, CDCl3) δ: 9.83 (1H, s), 8.20 (1H, s).