O-methyl-L-tyrosine N-Methylamide → 6-Methyl-4-[[[1-[(methylamino)carbonyl]-2-(4-methoxyphenyl)ethyl]amino]carbonyl]hept-3-enoic acid, methyl ester

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Reaction Steps

N,N-Dicyclohexylcarbodiimide (515 mg, 2.5 mmol) was added to an ice-cooled solution of 4-methoxycarbonyl-2-(2-methylpropyl)but-2-enoic acid (500 mg, 2.5 mmol) and O-methyl-L-tyrosine N-methylamide (520 mg, 2.5 mmol) in dry dichloromethane (30 ml), and the mixture was stirred at room temperature for 18 h. The precipitated solid was filtered off and washed with a little dichloromethane, then the organic solution was washed successively with 1 N hydrochloric acid (20 ml), 1 N sodium bicarbonate (20 ml), and water. The solution was dried (MgSO4) and evaporated in vacuo. Column chromatography (30 g silica) of the residual solid, eluting with 5% methanol/dichloromethane gave the title compound (520 mg, 53%), m.p. 142°-144° C. (dichloromethane/pentane).

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