1) By cyclization of methyl 2-(2,3-dichlorobenzylidene)acetoacetate (I) with isopropyl 3-amino-4-(carbamoyloxy)crotonate (II).
2) By cyclization of (I) with isopropyl 4-(carbamoyloxy)-2-butynoate (III) and ammonium acetate (IV).
By cyclization of (II) with 2,3-dichlorobenzaldehyde (V) and methyl acetoacetate (VI).
By esterification of 3-isopropyl 5-methyl 4-(2,3-dichlorophenyl)-2-hydroxymethyl)-6-methyl-1,4-dihydropyridine-3,5-dicarboxylate (VII) with chlorosulfonyl isocyanate.