Addition of 4-chlorophenylmagnesium bromide (II) to arecoline (I) in Et2O at -10 C afforded the corresponding 4-arylpiperidine-3-carboxylate as a mixture of trans (III) and cis (IV) isomers. After chromatographic isolation of the racemic cis isomer (IV), resolution employing dibenzoyl-D-tartaric acid furnished the dextro enantiomer (cis)(+)-(IV). Its epimerization in the presence of NaOMe produced a 1:5.6 mixture of cis/trans isomers, from which the major compound (-)-(trans)(III) was isolated by flash chromatography. Acid hydrolysis of its methyl ester group provided carboxylic acid (V), that was further converted to acid chloride (VI) using oxalyl chloride (1,2). Finally, coupling of (VI) with 1,8-octanediamine (VII) gave the title diamide.

Addition of 4-chlorophenylmagnesium bromide (II) to arecoline (I) in Et2O at -10 C afforded the corresponding 4-arylpiperidine-3-carboxylate as a mixture of trans (III) and cis (IV) isomers. After chromatographic isolation of the racemic cis isomer (IV), resolution employing dibenzoyl-D-tartaric acid furnished the dextro enantiomer (cis)(+)-(IV). Its epimerization in the presence of NaOMe produced a 1:5.6 mixture of cis/trans isomers, from which the major compound (-)-(trans)(III) was isolated by flash chromatography. Acid hydrolysis of its methyl ester group provided carboxylic acid (V), that was further converted to acid chloride (VI) using oxalyl chloride (1,2). Finally, coupling of (VI) with 1,8-octanediamine (VII) gave the title diamide.