Acetaldehyde, 2,2-dimethoxy- → N-(1H-benzimidazol-2-ylmethyl)-2,2-dimethoxyethanamine

Participants

Reaction Steps

To a MeOH 150 mL suspension of 1-(1H-benzimidazol-2-yl)methanamine dihydrochloride (4.0 g, 18.2 mmol) were added dimethoxyacetaldehyde (1.89 g, 18.2 mmol, 60 wt. % solution in water), sodium acetate (7.45 g, 91 mmol) and sodium cyanoborohydride (9.09 mL, 9.09 mmol, 1.0 M THF solution). The reaction mixture was stirred at room temperature overnight, concentrated under reduced pressure and reconstituted in DCM (150 mL). The resulting suspension was filtered. The filtrate was concentrated and chromatographed on silica gel with a gradient solvent mixture (5% MeOH-DCM to 15% MeOH-DCM over 15 CV) to give the title compound as oil (3.1 g). LC/MS: m/z 205(M+-OMe). 1H-NMR (CDCl3, 500 MHz) δ 3.02 (d, 1H), 3.36 (s, 6H), 4.40 (s, 211), 4.52 (t, 1H), 7.28-7.32 (m, 2H), 7.58-7.62 (m, 2H), 8.78-8.92 (br.s, 1H).

Provenance & Evidence