“…Latent cyclic C-nucleophiles such as 1,3-dimethylbarbituric acid (1,3-DMB), dimedone and Meldrum's acid, to name just the three most popular ones, are versatile reagents useful for many transformations in organic synthesis. [1,2,3] For example, they are often involved as nucleophilic partners in multicomponent condensation reactions, especially for the synthesis of diverse heterocyclic scaffolds. [1,2,4] Indeed, owing both to the facile deprotonation of their activated methylene and other positive attributes (e. g., wide variety of biological activities for barbituric acid and its derivatives, ambivalent electrophilic and nucleophilic reactivity modes for Meldrum's acid, …), they are therefore regarded as superior alternatives to malonate esters.…”