chromatographed on silica gel using hexane as the eluent charged 3 hydroxymethylindole 1 carboxylic acid tert butyl ester is added in to a flask and added dimethyl aminopyridine triethyl amine and thf at 0 u00b0 c maintained the reaction for 10 minutes and then added heptanoic anhydride drop wise slowly at 0 u00b0 c and maintained the reaction for 3 hours after completion of the reaction added citric acid solution to the reaction mixture and stirred well extract the reaction mass with ethyl acetate twice dried the organic layer over sodium sulfate and concentrated the organic layer at 40 u00b0 c thus obtained residue is chromatographed on silica gel using hexane as the eluent to a stirred solution of 3 hydroxymethyl indole 1 carboxylic acid benzyl ester in thf were added dmap and triethyl amine at 0 u00b0 c to this stirred reaction mixture propionic anhydride in thf was added maintained the reaction at 25 30 u00b0 c for 4 hrs after completion of the reaction reaction mass is concentrated thus obtained residue is dissolved in aqueous saturated sodium bicarbonate and aqueous layer was extracted with ethyl acetate twice organic layer was washed with 1 nhcl organic layer was concentrated to obtain crude material which is further purified over column chromatography dcm meoh charged 20 ml of thf magnesium turnings and 2 4 5 trifluoro bromo benzene in to a round bottom flask slowly cooled the reaction mass to u2212 5 to 0 u00b0 c added.