Benzaldehyde → 8-Benzylidene-2-methyl-5,6,7,8-tetrahydro-quinoline
Reaktionsgleichung
[CH3:1][C:2]1[CH:11]=[CH:10][C:9]2[CH2:8][CH2:7][CH2:6][CH2:5][C:4]=2[N:3]=1.[CH:12](=O)[C:13]1[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1.C(OC(=O)C)(=O)C.[OH-].[Na+]>>[CH:12](=[C:5]1[C:4]2[N:3]=[C:2]([CH3:1])[CH:11]=[CH:10][C:9]=2[CH2:8][CH2:7][CH2:6]1)[C:13]1[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1Komponenten
5
Versuchsvorschrift
A solution of Intermediate 200A1 (27.5 g, 187 mmol), benzaldehyde (18.4 mL, 181 mmol) and acetic anhydride (32.5 mL, 290 mmol) was heated at 155° C. for 4 h. The mixture was cooled to room temperature, mixed with crushed ice, basified with 2M NaOH to pH>8. The aqueous layer was extracted with hexane/ethyl acetate. The pooled organic layers were dried over MgSO4, filtered, evaporated and purified by chromatography on SiO2 to give 8-benzylidene-2-methyl-5,6,7,8-tetrahydro-quinoline (Intermediate 200A2) as the major product. This material was carried onto the next step. Note: 2-styryl-5,6,7,8-tetrahydro-quinoline (removed by chromatography on SiO2 with 1.5% acetone in hexanes) and 8-benzylidene-2-styryl-5,6,7,8-tetrahydro-quinoline were also produced as side products.