Condensation of 3'-chloro-4'-cyclohexylacetophenone (I) with semicarbazide hydrochloride (II) produced the semicarbazone (III). Treatment of (III) with selenium dioxide in HOAc generated the intermediate selenodiazole (IV) which, on further heating, gave rise to the aryl acetylene (V). Cupric chloride-catalyzed Mannich condensation of acetylene (V) with N-ethyl cyclohexylamine (VI) and formaldehyde yielded the propargyl amine (VII). Partial hydrogenation of the triple bond of (VII) using the Lindlar catalyst provided the target (Z)-propenyl amine, which was finally converted to the hydrochloride salt.

A different synthetic strategy was further reported. Fischer esterification of 4-cyclohexylbenzoic acid (VIII) with MeOH and H2SO4, followed by aromatic nitration of the resultant benzoate ester (IX), yielded methyl 4-cyclohexyl-3-nitrobenzoate (X). Nitro group reduction in (X) by transfer hydrogenation provided amine (XI). This was converted to the chloro derivative (XII) by application of a modified Sandmeyer reaction with tert-butyl nitrite and cupric chloride. Ester group reduction in (XII) with LiBH4, followed by Swern oxidation of the resultant alcohol (XIII), furnished aldehyde (XIV). The aminoethyl phosphonium salt (XVI) was prepared by addition of N-ethyl cyclohexylamine (VI) to vinyl triphenylphosphonium bromide (XV). The corresponding ylide generated in situ from phosphonium salt (XV) and potassium bis(trimethylsilyl)amide was then subjected to a Wittig reaction with aldehyde (XIV) to afford the title (Z)-propenyl amine.