5-((E)-2-Ethoxycarbonyl-vinyl)-1H-indole-2-carboxylic acid (0.427 g, 1.6 mmol) was dissolved in anhydrous DMF (20 ml). EDCl.HCl (0.38 g, 2 mmol), Et3N (0.59 ml, 4.3 mmol), HOBt (0.27 g, 2 mmol) and 7 amino heptanoic acid (tetrahydropyran-2-yloxy) amide (0.4 g, 1.6 mmol in anhydrous DMF 20 ml) were added and the reaction stirred at room temperature for 16 h under nitrogen. Water was added, the reaction mixture acidified to pH=6-7 (10% citric acid) and extracted with DCM. The organic layer was washed with 10% citric acid and saturated sodium hydrogen carbonate (×2). The solvent was removed in vacuo to give crude product which was purified by chromatography (EtOAc:hexane 1:2→EtOAc) to give the required product as a yellow solid (550 mg, 69% yield). LCMS purity 93%, m/z 488 [M++H]+
