N,N′-Diphenyldithiomalonamide as Methylene Active Thioamide: A First Synthesis of Stable Michael Adducts

N , N ′-Diphenyldithiomalonamide reacts with the 4-nitrobenzylidene derivative of Meldrum’s acid (or with Meldrum’s acid and 4-nitrobenzaldehyde) in the presence of a base to form crystalline Michael adducts. Structure of triethylammonium 2,2-dimethyl-5-(1-(4-nitrophenyl)-3-(phenylamino)-2-(phenylcarbamothioyl)-3-thioxopropyl)-4-oxo-4 H -1,3-dioxin-6-olate was studied by single crystal X-ray diffraction analysis.