Triethylamine → tert-butyl (3R)-3-[[(1S)-1-(4-methoxycarbonylphenyl)ethyl]carbamoyl]-3,4-dihydro-1H-isoquinoline-2-carboxylate

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Reaction Conditions

Reaction Steps

To a 0° C. mixture of (3R)-2-tert-butoxycarbonyl-3,4-dihydro-1H-isoquinoline-3-carboxylic acid (40.0 g, 141.4 mmol) and dichloromethane (784 mL), add triethylamine (21.7 mL, 155.5 mmol). Then add isobutyl chloroformate (20.3 mL, 155.5 mmol) in a dropwise fashion. After the end of the addition, stir the mixture at 0° C. for 20 minutes. Then, add methyl (S)-4-(1-aminoethyl)benzoate (27.9 g, 155.5 mmol), and stir the mixture at room temperature for 1 hour. Add water (400 mL), separate the layers, and wash the organic layer with 1 M aqueous KHSO4 (500 mL), followed by saturated aqueous NaHCO3 (500 mL). Dry the organic phase over MgSO4, filter to remove the solids, and concentrate the filtrate under reduced pressure to furnish the title compound as a white solid (60 g, 97% yield). Mass spectrum (m/z): 339 ([M+H−Boc]+), 383 ([M+H−t-Bu]+), 439 ([M+H]+).

Provenance & Evidence