Trifluoroacetic acid → N-ethyl-N-[(2R)-2-(thiazol-5-ylmethoxycarbonylamino)-3-phenylpropyl]-N-[(2S)-2-(thiazol-5-ylmethoxycarbonylamino)-3-phenylpropyl]amine

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Reaction Conditions

Reaction Steps

The product from Example 71B (86 mg, 0.17 mmol) in dichloromethane (1.8 mL) was treated with trifluoroacetic acid (1.0 mL) at ambient temperature. After stirring for 2 hours, the mixture was concentrated and treated with aqueous 10% K2CO3 (2.4 mL). The aqueous mixture was extracted with ethyl acetate (3×3 mL). The ethyl acetate extracts were combined and treated with 4-nitrophenyl 1,3-thiazol-5-ylmethyl carbonate [prepared from 4-nitrophenyl 1,3-thiazol-5-ylmethyl carbonate hydrochloride salt (99 mg, 0.35 mmol) by extraction with aqueous NaHCO3] in ethyl acetate (6 mL). After heat at 60° C. for 18 hours, the mixture was allowed to cool to ambient temperature and was concentrated. The residue was purified by flash column chromatography on silica gel eluting with (chloroform:methanol, 98:2) to provide the title compound (34.1 mg, 32%). 1H NMR (CDCl3) δ 8.78 (s, 2H), 7.85 (s, 2H), 7.32-7.05 (m, 10H), 5.40-5.17 (m, 6H), 4.20 (br s, 2H), 3.49-2.55 (m, 10H), 0.85 (t, 3H); MS (ESI+) m/z 594 (M+H)+.

Provenance & Evidence