Methylamine → (3-Chloro-7-fluoro-benzo[b]thiophen-2-ylmethyl)methylamine

Participants

Reaction Steps

A solution of 3-chloro-7-fluoro-benzo[b]thiophene-2-carbaldehyde (610 mg, 2.78 mmol) in CH3NH2 (20 mL of a 2.0 M solution in MeOH, 40 mmol) was stirred at room temperature overnight. The mixture was concentrated. The residue was dissolved in EtOH (20 mL), and after cooling in an ice bath, NaBH4 (159 mg, 4.20 mmol) was added. The mixture was slowly warmed to room temperature and then stirred overnight. The mixture was concentrated. The residue was taken up in NaOH (20 mL) and the mixture extracted with Et2O (3×). The combined organics were washed with satd NaCl, dried (Na2SO4) and concentrated. Purification by column chromatography (silica gel, 95:5 CH2Cl2/MeOH) gave the title compound (460 g, 70%) as a brown oil: 1H NMR (300 MHz, CDCl3) δ 7.56 (d, J=8.0 Hz, 1H), 7.38 (ddd, J=7.9, 7.9, 4.9 Hz, 1H), 7.06 (dd, J=8.8, 8.8 Hz, 1H), 4.09 (s, 2H), 2.53 (s, 3H), 1.55 (s, 1H).

Provenance & Evidence