3,5-Bis(ethoxy­carbon­yl)-2,6-dimethyl-1,4-dihydro­pyridine-4-carboxylic acid

The title mol­ecule, C(14)H(19)NO(6), was synthesized by the reaction of glyoxylic acid, ethyl acetoacetate and NH(4)HCO(3). In the crystal structure, the dihydro­pyridine ring adopts an asymmetric boat-type conformation with the C atom bearing the carboxyl group showing a signficantly larger deviation [0.325 (2) Å] from the base plane then the N atom [0.137 (2) Å]. One of the ethyl groups is disordered over two positions with occupancies of 0.741 (10) and 0.259 (10). The crystal is stabilized by strong inter­molecular hydrogen bonds. N—H⋯O inter­actions form infinite chains in the a direction. O—H⋯O hydrogen bonds form typical carboxylic acid dimers, which link the N—H⋯O chains into a ladder-type double chain.