Synthesis of 1,6-disubstituted 2,4-pyridinediones from 5-acetoacetyl-2,2-dimethyl-1,3-dioxane-4,6-dione

5-Acetoacetyl-2,2-dimethyl-1,3-dioxane-4,6-dione reacts with aliphatic amines and p-methoxy-aniline to afford the corresponding 5-[3-alkyl(or aryl)amino-2-butenoyl] derivatives. Heating of the latter in boiling toluene gives 86–90% of N-substituted 6-methylpyridine-3-carboxylic acids which undergo decarboxylation in diethylene glycol dimethyl ether at 160°C, leading to N-substituted 6-methyl-1,2,3,4-tetrahydro-pyridine-2,4-diones in high yields.Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 9, 2004, pp. 1376–1378.Original Russian Text Copyright © 2004 by Rubinov, Zheldakova, Rubinova.