Isopropanol → Ethyl cis-3,4-dimethyl-1-oxo-1,2,3,4-tetrahydropyrazino[1,2-a]indole-7-carboxylate

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Reaction Steps

Racemic cis-3,4-dimethyl-1-oxo-1,2,3,4-tetrahydropyrazino[1,2-a]indole-7-carboxylic acid (Intermediate F, 1.9 g, 6.7 mmol) is separated on a preparative chiral column (Chiralpak AD, 5 cm×50 cm, 20 u, Chiral Technologies, West Chester, Pa.) using Gilson preparative HPLC (Mobile Phase: 12% isopropanol in heptane; Flow rate: 100 mL/min) to afford ethyl (3S,4R)-3,4-dimethyl-1-oxo-1,2,3,4-tetrahydropyrazino[1,2-a]indole-7-carboxylate (870 mg, 46%) and ethyl (3R,4S)-3,4-dimethyl-1-oxo-1,2,3,4-tetrahydropyrazino[1,2-a]indole-7-carboxylate (852 mg, 45%).

Provenance & Evidence