4-AMINO-2-METHYLQUINOLINE

4295-06-1

6628-04-2

General procedure for the synthesis of 4-amino-2-methylquinoline from 2-methyl-4-chloroquinoline: In an oven-dried vial (35 × 12 mm) fitted with a PTFE-sealed screw cap, a magnetic stirring bar, [(±)-BINAP]Ni[P(OPh)3]2-2PhCH3 (39 mg, 0.025 mmol, 5 mol%), (±)- BINAP (15 mg, 0.025 mmol, 5 mol%) and the corresponding aryl halide (0.50 mmol, 1.0 equiv). The vial was transferred to an argon filled glove box and NaOtBu (216 mg, 2.20 mmol, 4.40 equiv) and NH3 (0.5 M in 1,4-dioxane, 3.0 mL, 1.5 mmol, 3.0 equiv) were added sequentially. After sealing the reaction vial, it was removed from the glove box and placed in an oil bath preheated to 120°C with stirring for 18 hours. After completion of the reaction, it was cooled to room temperature and the reaction mixture was diluted with ether (15 mL) and washed sequentially with 1 M NaOH (10 mL) and water (10 mL). The organic phase was dried over anhydrous sodium sulfate, concentrated and loaded onto silica gel, and purified by fast column chromatography (ethyl acetate/hexane or ethyl acetate/methanol) to afford the target product aniline analog. 4-Amino-2-methylquinoline (19 mg, 0.23 mmol, 46%) was obtained as an orange solid from 4-chloro-2-methylquinoline (100 mg, 0.500 mmol), operated according to the above general method and purified by fast column chromatography (ethyl acetate/methanol 90:10). The spectral data of the product were in agreement with literature reports [32]. Thin layer chromatography Rf = 0.23 (ethyl acetate/methanol 90:10).1H NMR (500 MHz, CDCl3) δ: 8.06 (1H, d, J = 8.4 Hz, Ar-H), 7.96 (1H, d, J = 8.4 Hz, Ar-H), 7.72 (1H, t, J = 7.7 Hz, Ar-H), 7.50 (1H, t, J = 7.7 Hz, Ar-H), 7.50 (1H, t, J = 7.7 Hz, Ar-H), 7.08 (1H, s, Ar-H), 2.66 (3H, s, CH3), 2.07 (2H, br s, NH2).13C NMR (125 MHz, CDCl3) δ: 159.6 (Ar-C), 149.2 (Ar-C), 145.8 (Ar-C), 130.1 (Ar-CH ), 129.5 (Ar-C), 125.6 (Ar-CH), 120.5 (Ar-CH), 120.1 (Ar-CH), 109.0 (Ar-CH), 25.7 (CH3).