Water → (4E)-N-Methyl-5-(5-ethoxy-3-pyridyl)-4-penten-2-amine Hemigalactarate

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Reaction Steps

To a solution of (4E)-N-methyl-5-(5-ethoxy-3-pyridyl)-4-penten-2-amine (151.4 mg, 0.68 mmol) in absolute ethanol (2.3 mL) was added galactaric acid (72.2 mg, 0.34 mmol). Water (0.5 mL) was added dropwise while gently warming the light-brown solution. The solution was filtered through glass wool to remove a few insoluble particles, washing the filter plug with ethanol-water (4:1, v/v) (1 mL). The filtrate was diluted with ethanol (3.4 mL), cooled to ambient temperature, and further cooled at 5° C. for 18 h. Because no precipitate had formed, the solution was concentrated on a rotary evaporator. The resulting solids were dried under high vacuum and recrystallized from 2-propanol-water. After cooling at 5° C. for 48 h the product was filtered, washed with cold 2-propanol, and vacuum dried at 45° C. for 6 h. Further vacuum drying at ambient temperature for 18 h afforded 168 mg (76.1%) of a white to off-white powder, mp 141-143.5° C.

Provenance & Evidence