2-Methoxyethyl acetoacetate → Isopropyl 2-methoxyethyl 4-(3-amino-2-chloro-phenyl)-1,4-dihydro-2,6-dimethyl-pyridine-3,5-dicarboxylate

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Reaction Steps

Isopropyl 2-methoxyethyl 4-(3-amino-2-chloro-phenyl)-1,4-dihydro-2,6-dimethyl-pyridine-3,5-dicarboxylate ##STR31## 27.5 g (61 mmol, purity 96.5%) of isopropyl 2-methoxy-ethyl 4-(2-chloro-3-nitrophenyl)-1,4-dihydro-2,6-dimethyl-pyridine-3,5-dicarboxylate, obtained by reaction of equimolar amounts of 2-chloro-3-nitrobenzaldehyde, isopropyl β-aminocrotonate and methoxyethyl acetoacetate in 2-propanol at the reflux temperature, are suspended in 500 ml of methanol and hydrogenated in the presence of Raney nickel (about 1.5 g, water-moist) under normal pressure and temperature until the end of the uptake of hydrogen (1 hour). The catalyst is filtered off and the residue obtained after concentration is purified by flash chromatography (toluene/ethyl acetate 1:0→5:1). Crystallization from toluene gives 24.0 g (93% of theory) of the title compound of melting point 118°-122° C.

Provenance & Evidence