1) By cyclization of 3-nitrobenzaldehyde (I) with methyl 3-aminocrotonate (II) and N-benzyl-3-pipendinyl acetylacetate (III) in refluxing THF.
2) By cyclization of methyl 3-nitrobenzylidene acetoacetate (IV) with (III) in refluxing THF.
3) By cyclization of (IV) with N-benzyl 3-piperidyl-3-aminocrotonate (V) in refluxing methanol.
4) By esterification of 1,4-dihydro-2,6-dimethyl 4-(3-nitrophenyl)pyridine-3,5-dicarboxylic acid monomethyl ester (VI) with 1-benzyl-3-hydroxypiperidine (VII) by means of SOCl2 in DMF dichloroethane.
5) The esterification of (VI) with 3-hydroxypipendine (VIII) as before gives the corresponding ester (IX), which is then benzylated with benzyl chloride (X) by means of triethylamine in refluxing THF.