Synthesis and Structure of 1-{2,2-Dimethyl-4,6-dioxo-5-(1-pyridinio)-1,3- dioxan-5-yl}pyridinium Ylide: A New Route to Meldrum’s Acid Derivatives

Starting with its discovery [1] and correct structural assignment [2], Meldrum’s acid (1) has become a widely used reagent in organic synthesis [3]. In general, nucleophilic attack occurs at the carbonyl carbon atoms followed by ring fragmentation. Under basic conditions, the anion acts as a nucleophile itself to generate methylene Meldrum’s acid (2) derivatives. In contrast to a great number of publications on reactions with organic electrophiles, reports dealing with nitrogen electrophiles including amine oxides [4], diazonium ions [5, 6], and the nitrite ion are rare [7]. Therefore, it seems useful to find a synthetic route to Meldrum’s acid derivatives starting from nitrogen nucleophiles.