3-Bromopropionic acid → 3-[2-bromo-3-cyclohexyl-6-(methoxycarbonyl)-1H-indol-1-yl]propanoic acid

Participants

Reaction Steps

NaH (3.5 eq, 60% dispersion in mineral oil) was added to a solution of methyl 2-bromo-3-cyclohexyl-1H-indole-6-carboxylate (prepared as described in WO 2004065367, from commercially available methyl indole-6-carboxylate) in DMF (0.2 M) and the solution allowed to stir at RT for 1 h. Then 3-bromopropanoic acid (1.1 eq) was added and the mixture stirred at RT for 2 h. DMF was concentrated in vacuo and the residue taken up in EtOAc. The organic phase was washed with 1 N HCl and then brine before being dried (Na2SO4), filtered and the solvent evaporated in vacuo. The title compound was used crude in the next step; MS (ES+) m/z 408 (M+H)+, m/z 410 (M+H)+.

Provenance & Evidence