To the stirred solution of 1-((1-tosyl-1H-indol-4-yl)methyl)-1,9-diazaspiro[5.5]undecan-2-one (TFA salt) (300 mg, 0.55 mmol) in DMF (6 mL) were added K2CO3 (380 mg, 2.75 mmol) and 2-chloro benzoxazole (101 mg, 0.66 mmol). The mixture was heated at 80° C. for 18 h. The reaction mixture was cooled to rt and concentrated under reduced pressure. To the crude mixture water was added and extracted with ethyl acetate. The organic layer was dried over anhydride sodium sulfate, filtered and concentrated to obtain a solid which was purified by flash column chromatography (eluent: 3% methanol in chloroform) to yield the title compound (250 mg, 80%). [LCMS RtE=1.75 min, [M+H]+=569.1].
