Benzaldehyde → 1-((3R)-6,8-Difluoro-3,4-dihydro-2H-1-benzopyran-3-yl)-1,3-dihydro-5-(2-((phenylmethyl)amino)ethyl)-2H-imidazole-2-thione

Participants

Reaction Conditions

Reaction Steps

To (R)-5-(2-aminoethyl)-1-(6,8-difluorochroman-3-yl)-1H-imidazole-2(3H)-thione (2.36 g, 7.58 mmol) in a mixture of Methanol (15.00 ml) and Dichloromethane (15 ml) was added BENZALDEHYDE (0.845 ml, 8.34 mmol). To the resulting clear solution SODIUM CYANOBOROHYDRIDE (0.702 g, 10.61 mmol) was added in portions at 20-25° C. to avoid intensive foaming and the solution was stirred at 20-25° C. for 40 h. The solution was quenched at 20-25° C. with 1N HCl (12 ml), neutralised with 3N NaOH (12 ml), the mixture was extracted with DCM (100 ml). The organic phase was washed with brine, dried (MgSO4), evaporated to dryness. The residue was purified on a column with EA-MeOH 9:1 as eluent, fractions collected, concentrated to approx 20 ml, cooled in ice. The precipitate collected, washed with Ethyl Acetate-Petroleum Ether 1:1, dried on air to give (R)-5-(2-(benzylamino)ethyl)-1-(6,8-difluorochroman-3-yl)-1H-imidazole-2(3H)-thione (1.55 g, 3.86 mmol, 50.9% yield).

Provenance & Evidence