Ethyl Acetate → HCID 15598548, compound

Participants

Reaction Steps

To a mixture of L-proline-tert-butyl ester hydrogen chloride salt 75 (0.5 g, 2.9 mmol) in dichloromethane (50 mL) was added 76 (0.98 g, 2.99 mmol), DIPEA (756 mg, 4.35 mmol) and HATU (1.3 g, 3.5 mmol). The reaction mixture was allowed to stir at an ambient temperature for 16 h. The mixture was poured into ethyl acetate (100 mL) and was washed with 0.2 N HCl (50 mL), water (50 mL), brine (50 mL) and dried over MgSO4. Chromatography was conducted on a 2 mm radial chromatotron plate eluting with 10% ethyl acetate in hexanes. Product-containing fractions were concentrated under reduced pressure, dissolved in dichloromethane (8 mL) and treated with piperidine (2 mL). The mixture was stirred for 1 h, concentrated under reduced pressure and purified on a 2 mm radial chromatotron plate eluting with 5% methanol/dichloromethane. This gave 200 mg (26%) of the dipeptide 74: 1H-NMR (400 MHz, CDCl3) δ 4.41 (m, 1H), 4.17 (m, 1H), 3.82 (m, 1H), 3.57 (m, 4H), 3.2 (m, 1H), 2.82 (m, 1H), 2.83-1.65 (m, 5H), 1.44 (m, 9H).

Provenance & Evidence