Ammonia → 6-chloro-3-methyl-3,4-dihydro-2H-isoquinolin-1-one
Reaction equation
C[O:2][C:3](=O)[NH:4][CH:5]([CH3:14])[CH2:6][C:7]1[CH:12]=[CH:11][CH:10]=[C:9]([Cl:13])[CH:8]=1.N>>[Cl:13][C:9]1[CH:8]=[C:7]2[C:12](=[CH:11][CH:10]=1)[C:3](=[O:2])[NH:4][CH:5]([CH3:14])[CH2:6]2Participants
3
Conditions
- Temperature
- 120 °C
Procedure
Under N2 protection, a mixture of [2-(3-chloro-phenyl)-1-methyl-ethyl]-carbamic acid methyl ester (1.2 g, 5.3 mmol) and PPA (polyphosphoric acid) (10 g) in a 100 mL round bottom flask was stirred at 120° C. for 2 hours. After cooling to room temperature, the reaction mixture was treated with ice-water and aqueous ammonia solution to adjust the pH to 8. The mixture was then extracted with ethyl acetate and the organic layer was washed with brine, dried over anhy. Na2SO4, filtered and concentrated in vacuo. The crude product obtained was further washed with ether to give 6-chloro-3-methyl-3,4-dihydro-2H-isoquinolin-1-one (0.27 g, 26%) (intermediate A-3-1) as a white solid. MS: 196.1 (M+H+). The ether filtrate was concentrated under reduced pressure and purified by flash chromatography to afford 8-chloro-3-methyl-3,4-dihydro-2H-isoquinolin-1-one (intermediate A-3-2) (54 mg, 5.2%) as a white solid. MS: 196.1 (M+H+).