Coupling of 4(S)-amino-4-carboxybutyric acid methyl ester (I) to acyl chloride (II) by means of Et3N in CH2Cl2 provides derivative (III), which is then converted into hydroxy derivative (IV) by means of N-hydroxysuccinimide (A) and DCC in THF followed by reduction with NaBH4 in H2O. Treatment of (IV) with ethoxymethylchloride (V) and DIEA in CH2Cl2 affords compound (VI), which is then methylated by means of lithium bis(trimethylsilyl)amide and methyl iodide in THF to give derivative (VII). Saponification of methyl ester (VII) by treatment with aqueous NaOH in THF affords carboxylic acid (VIII), which is then coupled to N-(1-methoxy-1,1-dimethyloxy)amine (IX) by means of HOBt and EDC in DMF and finally hydrolyzed with HCl in MeOH to furnish the target compound.