2-(2-Aminoethyl)-1-methylpyrrolidine → 2-(cyclohexylmethyl)-N-{2-[(2S)-1-methylpyrrolidin-2-yl]ethyl}-1,2,3,4-tetrahydroisoquinoline-7-sulfonamide

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Reaction Steps

WO2005/118547 describes a general method of synthesis which is difficult to transpose to the industrial scale for production in large quantities. This method of synthesis entails reacting 2-(2,2,2-trifluoroacetyl)-1,2,3,4-tetrahydro-isoquinoline-7-sulfonyl chloride with (+/−)-2-(2-aminoethyl)-1-methylpyrrolidine, which product is deprotected in methanol and hydrochloric acid. The enantiomers are next separated by chiral chromatography. The resulting N-{2-[(2S)-1-methylpyrrolidin-2-yl]ethyl}-1,2,3,4-tetrahydroisoquinoline-7-sulfonamide undergoes reductive amination with cyclohexanecarboxaldehyde in the presence of a palladium catalyst. 2-(Cyclohexylmethyl)-N-{2-[(2S)-1-methylpyrrolidin-2-yl]ethyl}-1,2,3,4-tetrahydroisoquinoline-7-sulfonamide is isolated as the free base and converted to a salt.

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