7-Benzofuranmethanamine, N-methyl- synthesis

Yield:389806-25-1 71%

Reaction Conditions:

with sodium tetrahydroborate in methanol;water at 0 - 20;

Steps:

5.A Example 5; Step A

Benzofuran-7-carboxaldehyde (4.44 g, 30.4 mmol), aqueous methylamine (5.5 mL, 63 mmol) and MeOH (35 mL) were combined in a 25-mL flask under N₂. The mixture was cooled to 0° C. under rapid stirring, and NaBH₄ (0.61 g, 16 mmol) was added in portions over 5 min. The mixture warmed to room temperature while stirring overnight. The mixture was diluted with water (50 mL), stirred for 15 mm, and extracted (3*) with CH₂Cl₂. The combined organic extracts were washed (3*) with 2 N HCl. These acidic extracts were made basic with solid KOH, additional water, and conc. NH₄OH. The basic mixture was extracted (3*) with CH₂Cl₂. This second set of organic extracts were combined and dried over Na₂SO₄, filtered, and concentrated in vacuo to provide the methyl amine product (3.51 g, 71%) as a yellow oil: ¹H NMR(500 MHz, CDCl₃) δ7.66 (d, J=2.3 Hz, 1 H), 7.53-7.55 (m, 1 H), 7.22-7.29 (m, 2 H), 6.80 (d, J=2.4 Hz, 1 H), 4.10 (s, 2 H), 2.51 (s, 3 H).

References:

US2006/111385,2006,A1 Location in patent:Page/Page column 15