Benzo[b]thiophene-3-ethanamine → N-[2-(1-Benzothien-3-yl)ethyl]-N-(8-methyl-2,3-dihydro-[1,4]dioxino[2,3-f]quinolin-2-ylmethyl)amine

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Reaction Steps

To a stirred solution of 2-benzo[b]thiophen-3yl-ethylamine (354 mg, 2.0 mmol) in 1 mL of anhydrous DMSO was added [(2R)-8-methyl-2,3-dihydro[1,4]dioxino[2,3-f]quinolin-2-yl]methyl 4-bromo-benzenesulfonate (300 mg, 0.67 mmol). The reaction mixture was stirred at ambient temperature for 4 days. The reaction was diluted with H2O (10 mL), poured into saturated aqueous sodium bicarbonate (25 mL) and extracted with ethyl acetate (3×25 mL). The combined organic layers were washed with 1:1 H2O/brine (40 mL) and brine (40 mL), then were dried over anhydrous magnesium sulfate, filtered, and concentrated in vacuum. Flash chromatography (2×20 cm SiO2, CH2Cl2 to 3% MeOH/CH2Cl2 gradient) afforded 225 mg (86%) of the (S)-enantiomer of the title compound as a thick oil. The fumarate salt was prepared by treating the amine in ethyl acetate with a solution of 66 mg (0.57 mmol) fumaric acid in methanol. The precipitated salt, a pale yellow solid, weighed 190 mg (m.p. 124-127° C.); MS (ESI) m/z 391 [M+H]+.

Provenance & Evidence