Diisopropylethylamine → (R)-3-(4-carboxybutanoyl-amino)-3-(4-aminophenyl)-propanoic acid methyl ester

참여 물질

반응 단계

A mixture of (R)-3-amino-3-[4-(tert-butoxycarbonylamino)phenyl]-propanoic acid methyl ester [1.5 g, Reference Example 7(c)], mono-methyl glutarate (0.7 ml), O-(7-azabenzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (2.05 g), diisopropylethylamine (1.8 ml) and dimethylformamide (40 ml) was stirred at ambient temperature for 18 hours. The reaction mixture was evaporated to dryness and diluted with water (75 ml) and the resultant mixture acidified to pH1.0 by addition of concentrated hydrochloric acid. The mixture was extracted twice with ethyl acetate (75 ml). The combined extracts were washed with water (75 ml) then dried over magnesium sulphate and then evaporated. The resulting waxy fawn solid (3.8 g) was dissolved in dichloromethane (20 ml), cooled to 0° C., and the solution treated with trifluoracetic acid (4 ml). After stirring at ambient temperature for 2 hours the reaction mixture was evaporated and the residue taken up in ethyl acetate (50 m). The resultant solution was treated with ice cold saturated aqueous potassium carbonate solution (20 ml) with stirring at ambient temperature for 5 minutes. The organic layer was separated, washed with water (30 ml), dried over magnesium sulphate, and then evaporated to give (R)3-(4-carboxybutanoyl-amino)-3-(4-aminophenyl)-propanoic acid methyl ester (1.32 g) as a yellow oil.

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