合成路线1

Diazotization of 3,5-dichloroaniline (I), followed by reduction of the resultant diazonium salt provides hydrazine (II). Subsequent reaction of 3,5-dichlorophenylhydrazine (II) with ethyl pyruvate (III) under Fischer reaction conditions gives rise to indole (IV). Vilsmeier formylation of (IV) using N-methylformanilide and phosphoryl chloride produces aldehyde (V). This is reductively aminated with methyl glycinate and NaBH(OAc)3 to afford aminoester (VI). Condensation of (VI) with phenyl isocyanate, followed by cyclization in the presence of Et3N leads to hydantoin (VII). Finally, ester (VII) is hydrolyzed employing LiOH to furnish the target indolecarboxylic acid.