This compound can be obtained in two different ways: 1) The reaction of 8-(4-chlorophenyl)-8-aza-1,4-dioxaspiro[4.5]decane-2-methanol (I) with 5-acetyl-2,2-dimethyl-1,3-dioxane-4,6-dione (acetylated Meldrum's acid, II) in refluxing toluene gives the corresponding acetylacetic ester (III), which by reaction with NH3 in dry dichloromethane is converted into the 3-aminocrotonic ester (IV). Finally, this compound is cyclized with methyl 2-(3-nitrobenzylidene)acetylacetate (V) in refluxing tert-butanol. 2) The partial hydrolysis of 2,6-dimethyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-(2,2-dimethyl-1,3-dioxolan-4-ylmethyl) 5-methyl diester (VI) with HCl 1N in methanol gives the corresponding glycerol ester (VII), which is then spiranized with 1-(4-chlorophenyl)-4-piperidone (VIII) by means of p-toluenesulfonic acid in refluxing methanol.

This compound can be obtained in two different ways: 1) The reaction of 8-(4-chlorophenyl)-8-aza-1,4-dioxaspiro[4.5]decane-2-methanol (I) with 5-acetyl-2,2-dimethyl-1,3-dioxane-4,6-dione (acetylated Meldrum's acid, II) in refluxing toluene gives the corresponding acetylacetic ester (III), which by reaction with NH3 in dry dichloromethane is converted into the 3-aminocrotonic ester (IV). Finally, this compound is cyclized with methyl 2-(3-nitrobenzylidene)acetylacetate (V) in refluxing tert-butanol. 2) The partial hydrolysis of 2,6-dimethyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-(2,2-dimethyl-1,3-dioxolan-4-ylmethyl) 5-methyl diester (VI) with HCl 1N in methanol gives the corresponding glycerol ester (VII), which is then spiranized with 1-(4-chlorophenyl)-4-piperidone (VIII) by means of p-toluenesulfonic acid in refluxing methanol.