Ethyl 3-(triphenyl-lambda~5~-phosphanylidene)propanoate → t-butyl 4-[6-(N-cyclopentylmethylcarbamoyl)-3-(2-ethoxycarbonyl-1-propenyl)indol-1-ylmethyl]-3-methoxybenzoate

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Reaction Steps

A solution of t-butyl 4-[6-(N-cyclopentylmethylcarbamoyl)-3-formylindol-1-ylmethyl]3-methoxybenzoate (Example 1, part(f)) (2.8 g) and (carbethoxyethylidene)triphenylphosphorane (4.6 g) in dioxane (29 ml) was heated at reflux for 18 hours. The solvent was evaporated. The resultant residue was purified by flash chromatography on silica gel (192 ml), eluting with 1:4 ethyl acetate:hexane to give t-butyl 4-[6-(N-cyclopentylmethylcarbamoyl)-3-(2-ethoxycarbonyl-1-propenyl)indol-1-ylmethyl]-3-methoxybenzoate (3.3 g, 100%) as a light yellow solid; mp 118°-120°; NMR (80 MHz, CDCl3) 2.15(d, 3H, CCH3), 3.40(dd, 2H, NHCH2), 5.42(s, 2H, NCH2), 6.22(br t, 1H, NH), 6.78(d, 1H, Ar).

Provenance & Evidence