2,4-Dimethylbenzylamine → 6,8-Dimethylisoquinolin-3-amine

Participants

Reaction Conditions

Reaction Steps

To a solution of methyl 2,2-diethoxyacetimidate (1.5 g, 9.3 mmol) in methanol (4.9 mL) was added (2,4-dimethylphenyl)methanamine (1.2 g, 8.9 mmol) dropwise at ambient temperature. The reaction flask was then placed into a preheated oil-bath and stirred at 70° C. for 16 h, then cooled and the volatiles removed under reduced pressure. The crude material was added dropwise to sulfuric acid (19.7 mL) at ambient temperature and stirred for 72 h. The flask was then placed into an ice-water bath, diluted with water (50 mL), and slowly neutralized to pH=10 with sodium hydroxide (10 N). As the reaction mixture became basic, an orange precipitate formed. This precipitate was filtered, washed with water, and dried to afford 6,8-dimethylisoquinolin-3-amine (1.37 g, 7.95 mmol, 90%). 1H NMR (400 MHz, MeOD) δ ppm 8.82 (s, 1H), 7.17 (s, 1H), 6.90 (s, 1H), 6.72 (s, 1H), 2.61 (s, 3H), 2.37 (s, 3H). MS (LC/MS) R.T.=0.77; [M+H]+=173.15.

Provenance & Evidence