Hantzsch ester refers to an organic compound with the formula HN(MeC=C(CO<sub>2</sub>Et))<sub>2</sub>CH<sub>2</sub> where Me = methyl (CH<sub>3</sub>) and Et = ethyl (C<sub>2</sub>H<sub>5</sub>). It is a light yellow solid. The compound is a 1,4-dihydropyridine. It is named after Arthur Rudolf Hantzsch who described its synthesis in 1881. The compound is a hydride donor, e.g., for reduction of imines to amines. It is a synthetic analogue of NADH, a naturally occurring dihydropyridine.
Hantzsch ester can be made with a Hantzsch pyridine synthesis where formaldehyde, two equivalents of ethyl acetoacetate and ammonium acetate are combined to afford the product in high yield.
As confirmed by X-ray crystallography, Hantzsch ester has a planar C<sub>5</sub>N core.