Acetic Acid → N2,N2-Diethyl-1-[4-(propylsulphonyl)phenyl]ethane-1,2-diamine

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Reaction Steps

To a solution of N1,N1-diallyl-1-[4-(propylsulphonyl)phenyl]ethane-1,2-diamine (473 mg, 1.47 mmol, prepared as described in Example 47c in methanol (10 mL) was added acetaldehyde (approximately 0.5 mL, approx. 9 mmol), acetic acid (0.42 mL, 7.3 mmol) and finally, sodium cyanoborohydride (203 mg, 3.2 mmol). The mixture was stirred at room temperature, under nitrogen, overnight and then quenched by addition of satd. NaHCO3(aq). Methanol was removed in vacuo, the residue diluted with water and the product extracted into ethyl acetate (×3). The combined organic extracts were washed with brine, dried (MgSO4) and concentrated. The crude material was dissolved in dichloromethane and to this solution was added 1,3-dimethylbarbituric acid (1.37 g, 8.8 mmol) and palladium (tetrakis)triphenylphosphine (85 mg, 0.07 mmol). The mixture was heated at reflux for 6 h, then cooled and concentrated. The title compound was partially purified using an SCX cartridge (330 mg obtained, 75% yield over two steps, approximate since not pure). m/z (ES+) 282 (M−NH2).

Provenance & Evidence