4-Methylmorpholine → Trans-N-[(2R)-2-phenylpropanoyl]-3-amino-1,2,3,4-tetrahydro-2-naphthalenol

関与物質

反応条件

反応手順

Under argon to a solution of R-(-)-2-phenylpropionic acid (505 mg) in methylene chloride (10 ml) at 0° C. was added hydroxybenzotriazole, hydrate (530 mg) and dicyclohexylcarbodiimide (718 mg). The mixture was stirred at 0° C. for 10 minutes before addition of racemic trans-3-amino-1,2,3,4-tetrahydro-2-naphthalenol, hydrochloride (723 mg) and N-methylmorpholin (438 mg) in methylene chloride (5 ml). Stirring was maintained at 0° C. for 3 hours and at room temperature overnight. The reaction mixture was diluted with ethyl acetate and filtered. Evaporation of solvent gave the crude mixture of diastereoisomer A and diastereoisomer B. The diastereoisomer separation was achieved by chromatography on silica gel [160 g, elution with ethyl acetate: cyclohexane, 1:9 (700 ml), 2:8 (1 1), 3:7 (1 1) 2:3 (1 1) and 1:1 (1 1)]. Diastereoisomer A obtained as a white solid (232 mg) was recrystallized in ethyl acetate/cyclohexane, m.p. 158° C., Rf=0.30 (silica gel, ethyl acetate:cyclohexane, 1:1). Diastereoisomer B was recovered as a white solid (250 mg) and recrystallized in ethyl acetate, m.p. 179-180° C., Rf=0.40 (silica gel, ethyl acetate:cyclohexane, 1:1).

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