合成路线1

The nitration of 2,5-dichlorotoluene (I) with HNO3 in H2SO4/AcOH gives 2,5-dichloro-4-methylnitrobenzene (II), which is treated with t-butoxybis(dimethylamino)methane (III) in refluxing THF to yield 2,5-dichloro-4-[2-(dimethylamino)vinyl]nitrobenzene (IV). The condensation of (IV) with 1-(1,2-benzoisothiazol-3-yl)piperazine (V) in AcOH affords the disubstituted piperazine (VI), whose double bond is reduced by means of NaBH(OAc)3 in dichloroethane/AcOH to provide the saturated compound (VII). The condensation of (VII) with dimethyl malonate (VIII) by means of KOH in NMP gives the alkylated malonic ester (IX), which is hydrolyzed and monodecarboxylated with refluxing 3N HCl to yield the phenylacetic acid (X). The esterification of (X) with SOCl2 and methanol affords the methyl ester (XI), which is finally cyclized to the target indolone by reduction of its nitro group with sodium hydrosulfite in refluxing THF/ethanol. Alternatively, compound (VII) can be condensed with methyl cyanacetate (XII) by means of KOH in NMP to give the alkylated cyanacetic ester (XIII), which is hydrolyzed with refluxing 3N HCl to afford the already reported phenylacetic acid (X).