N-Acetyl-tyrosinyl-valinyl-4-allyloxyproline → N-(N-Acetyl-tyrosinyl-valinyl-(4(R)-allyloxyprolinyl))-3(S)-amino-4-oxobutanoic acid tert-butyl ester semicarbazone

Participants

Reaction Steps

N-Acetyl-tyrosinyl-valinyl-(4-allyloxyproline) methyl ester (770 mg, 1.57 mmol) was dissolved in 20 ml of tetrahydrofuran and 4 ml of methanol. Lithium hydroxide (145 mg, 3.46 mmol) was added to the mixture and stirred at room temperature. After two hours, 1 ml of 10% hydrogen chloride was added and the mixture evaporated in vacuo to give a solid residue then partitioned between Sml of water and 50 ml of ethyl acetate and the organic layer separated and evaporated in vacuo to give 430 mg of the acid that waa used immediately in the next step. N-Acetyl-tyrosinyl-valinyl-4-allyloxyproline (420 mg, 0.88 mmol) and 3-amino-4-oxobutyric acid tert-butyl ester semicarbazone (184 mg, 0.8 mol, Graybill et al., Int. J. Protein Res., 44, pp. 173-82 (1994)) to give 100 mg (20%) of the title compound as a white amorphous solid: 1H NMR (CD3OD) δ7.24-7.2 (1H, m), 7.04-6.97 (2H, d), 6.73-6.65 (2H, d), 5.98-5.86 (1H, m), 5.35-5.24 (1H, d), 5.17-5.12 (1H, m), 4.12-3.98 (2H, m), 3.72-3.67 (1H, m), 2.98-2.92 (3H, m), 2.38-2.32 (1H, m), 2.1-2.02 (2H, m), 1.92 (3H, s), 0.98-0.89 (6H, 2×d).

Provenance & Evidence