Hexamethylenetetramine → Methyl 4-formyl-3-hydroxybenzoate
Reaktionsgleichung
[OH:1][C:2]1[CH:3]=[C:4]([CH:9]=[CH:10][CH:11]=1)[C:5]([O:7][CH3:8])=[O:6].C1N2CN3CN(C2)CN1C3.FC(F)(F)[C:24](O)=[O:25]>>[CH:24]([C:3]1[C:2]([OH:1])=[CH:11][CH:10]=[CH:9][C:4]=1[C:5]([O:7][CH3:8])=[O:6])=[O:25].[CH:24]([C:11]1[CH:10]=[CH:9][C:4]([C:5]([O:7][CH3:8])=[O:6])=[CH:3][C:2]=1[OH:1])=[O:25]Komponenten
5
Versuchsvorschrift
Methyl 3-hydroxybenzoate (75.5 g) is dissolved in trifluoroacetic acid (2 L), thereto is added hexamethylenetetramine (141.4 g) at room temperature and the mixture is heated under reflux for 3 hours. The reaction solution is concentrated under reduced pressure, to the resulting residue is added water, the mixture is adjusted to pH 8 with potassium carbonate and sodium hydrogen carbonate, diluted with water and extracted with ethyl acetate. The organic layer is washed with saturated brine, dried over sodium sulfate and evaporated to remove the solvent under reduced pressure. The resulting residue is purified by silica gel column chromatography (eluent: hexane/ethyl acetate=8/1, 5/1 followed by 2/1) to give methyl 2-formyl-3-hydroxybenzoate (54.6 g) (ESI-MS m/z: 179[M−H]−) and methyl 4-formyl-3-hydroxybenzoate (4.4 g)