Synthesis and X‑ray Characterization of Alkali Metal 2‑Acyl-1,1,3,3-tetracyanopropenides

A novel route for
synthesis of 2-acyl-1,1,3,3-tetracyanopropenides
(ATCN) salts in high yields and excellent purities starting from readily
available methyl ketones, malononitrile, bromine, and alkali metal
acetates is reported. The starting aryl­(heteroaryl) methyl ketones
were oxidized to the corresponding α-ketoaldehydes by new a
DMSO–NaBr–H2SO4 oxidation system
in yields up to 90% within a short reaction time of 8–10 min.
The subsequent stages of ATCN preparation are realized in aqueous
media without use of any toxic solvents, in accordance with principle
5 of “green chemistry”. Lithium, sodium, potassium,
rubidium, and cesium 2-benzoyl-1,1,3,3-tetracyanopropenides were characterized
by X-ray diffraction analysis. These salts show a good potential for
synthesis of five- and six-membered heterocycles and may serve as
potentially useful ligands in coordination and supramolecular chemistry.