Reaction Steps
N-(Tert-butoxycarbonyl-valinyl-alaninyl)-4-amino-5-benzyloxy-2-oxotetrahydrofuran (590.4 mg) was dissolved in 15 mL of trifluoroacetic acid, aged for 15 minutes, and concentrated. The residue was dissolved in methanol, diluted with toluene and concentrated to give a colorless solid. To 202.6 mg of this solid was added 3-(4-hydroxyphenyl)-propionic acid (137 mg, 0.8245 mmol), hydroxybenzotriazole (111 mg, 0.8245 mmol), dimethyl formamide (3 mL), and 4-methylmorpholine (45 μL, 0.4122 mmol). Ethyl dimethylaminopropyl carbodiimide (83 mg, 0.433 mmol) was added and the mixture stirred for 16 hours at ambient temperature. The mixture was diluted with ethyl acetate and washed three times with 2N hydrochloric acid, and twice with dilute sodium bicarbonate. The organics were dried over sodium sulfate, filtered, and concentrated to give the title compound as a mixture of two diastereomers: 1H NMR (400 MHz, CD3OD) δ7.4-7.2 (m, 5H, Ar--H), 7.01 (2d's, 2H, Ar--H), 6.66 (d, 2H, Ar--H), 4.9-4.6 (m, 2.5H, CH2Ph, CHN), 4.4-4.2 (m, 1.5H, CHN), 4.08 (d, 0.5H, J=7.43 Hz, CHN), 4.02 (d, 0.5H, J=7.15 Hz, CHH, 3.03 (dd, 0.5H, J=8.25, 18.31 Hz, CHHCO2), 2.9-2.7 (m, 2.5H, CHHCO2, CH2CON), 2.60 (dd, 0.5H, J=10.19, 17.29 Hz, CHHCO2), 2.55-2.45 (m, 2.5H, CHHCO2, CH2CH2 p--HOPh), 1.97 (m, 1H, CH(CH3)2), 1.32 (d, 1.5H, J=7.14 Hz, CHCH3), 1.26 (d, 1.5H, J=7.14 Hz, CHCH3), 0.9-0.8 (m, 6H, CH(CH3)2). ##STR35## N-(3-Phenylpropionyl-valinyl-alaninyl)-4-amino-5-benzyloxy-2-oxotetrahydrofuran
