反应详情

2,6-Diisopropylaniline (9.4 mL, 50 mmol, Aldrich) was mixed with isobutyric aldehyde (9.1 mL, 100 mmol, Aldrich), p-toluenesulfonic acid (0.48 g, 2.5 mmol, Aldrich), chloroform (50 mL) and MgSO4 (12 g, 100 mmol). The mixture was stirred for 2 h at RT. Assay by 1H-NMR (crude reaction mixture) showed the presence of product and starting material (8/1 ratio). The reaction mixture was filtered, the precipitate washed with chloroform (50 mL), and 5 Å molecular sieves were added. After stirring for 20 h at RT the solution was filtered, the molecular sieves were washed with chloroform (2×50 mL), the solvent was evaporated, and the residue distilled at reduced pressure. After a few drops of forerun (67–76° C./27 Pa) product was collected at 76–77° C./27 Pa as a colorless oil, 8.66 g (74.8%). 1H NMR (CDCl3) 7.60 (d, 1H; J=4.8 Hz); 7.20–7.05 (m, 3H); 3.00 (septet, 2H; J=6.8 Hz); 2.78 (d of septets, 1H; J=4.8; 6.7 Hz); 1.33 (d, 6H; J=6.7 Hz); 1.23 (d, 12H; J=6.8 Hz).

1. customAssay by 1H-NMR (crude reaction mixture)
2. filtrationThe reaction mixture was filtered
3. washthe precipitate washed with chloroform (50 mL), and 5 Å molecular sieves
4. additionwere added
5. stirringAfter stirring for 20 h at RT the solution
6. filtrationwas filtered
7. washthe molecular sieves were washed with chloroform (2×50 mL)
8. customthe solvent was evaporated
9. distillationthe residue distilled at reduced pressure
10. customAfter a few drops of forerun (67–76° C./27 Pa) product was collected at 76–77° C./27 Pa as a colorless oil, 8.66 g (74.8%)