Eletriptan → (R)-1-acetyl-5-(benzenesulfonylethenyl)-3-(N-methyl-pyrrolidin-2-ylmethyl)-1H-indole

Participants

Reaction Steps

As a result of this difficulty, we have now developed an alternative route to eletriptan which avoids the use of a precursor which is prone to dimerisation. Specifically, the process of the invention comprises the preparation of eletriptan by the hydrolysis of (R)1-acetyl-5-(2-benzenesuiphonylethyl)-3-(N-methylpyrrolidin-2-ylmethyl)-1H-indole, which compound may conveniently be prepared by (i) N-acetylating (R)-5-bromo-3-(N-methylpyrrolidin-2-ylmethyl)-1H-indole, (ii) reacting the resulting (R)-1-acetyl-5-bromo-3-(N-methylpyrrolidin-2-ylmethyl)-1H-indole with phenyl vinyl sulphone in the presence of a palladium catalyst, a triarylphosphine and a base to give (R)-1-acetyl-5-(2-benzenesulphonylethenyl)-3-(N-methylpyrrolidin-2-ylmethyl)-1 H-indole and (iii) catalytically reducing same.

Provenance & Evidence