5-(4-PYRIDYL)-1,3-DIOXAN-4,6-DIONES - PREPARATION AND REACTIONS WITH O-NUCLEOPHILES, N-NUCLEOPHILES AND C-NUCLEOPHILES

The reaction between alkyl chloroformates, pyridine and 1,3-dioxane-4,6-diones 5-[1-alkoxycarbonyl-4(1H)-pyridylidene]-1,3-dioxane-4,6-diones 3 via the dihydro intermediates 2. The compounds 3 transfer the alkoxycarbonyl group readily to O-, N- and C-nucleophiles. Hydrolysis of 3a-e affords 2,2-dimethyl-5-(4-pyridyl)-1,3-dioxane-4,6-dione (4a), which in solution exists in the NH tautomeric form. Nucleophilic reagents attack 4a at one of the carbonyl groups to yieLd derivatives of (4-pyridyl)acetic acid. These reactions admit a convenient access to a number of 4-pyridyl-substituted heterocycles.