合成路线1

Condensation of 2,5-dibromonitrobenzene (I) with diethyl malonate gave aryl malonate (II). Reductive cyclization of (II) in the presence of tin and HCl produced 6-bromooxindole (III), which was further reduced to indoline (IV) using borane-dimethyl sulfide complex. Reductive alkylation of indoline (IV) with piperidone (V) by means of sodium triacetoxyborohydride furnished the piperidinyl indoline (VI). Introduction of a formyl group into indoline (VI) was carried out via lithiation with n-butyllithium, followed by treatment with dimethylformamide. The resulting aldehyde (VII) was reduced to alcohol (VIII) using NaBH4. Conversion to the corresponding chloride by treatment with HCl, followed by reaction with NaCN, furnished nitrile (IX). Hydrolysis of nitrile (IX) with aqueous H2SO4 gave carboxylic acid (X), which, after activation with carbonyldiimidazole, was coupled with methylamine to yield amide (XI). Finally, indoline (XI) was oxidized to the title indole with MnO2 in CHCl3. Alternatively, Stille coupling of bromoindoline (VI) with ethyl tributylstannylacetate gave indolineacetate (XII), which was further oxidized to indole (XIII) with MnO2. Saponification of the ester group of (XIII), followed by condensation with methylamine furnished the title compound.