Magnesium Nitride Serves Up Ammonia

Magnesium nitride (Mg₃N₂) is a convenient source of ammonia for a host of reactions that produce nitrogen-containing compounds, a University of Cambridge research team reports (Org. Lett., DOI: 10.1021/ol801398z). The stable low-cost commercially available reagent, which produces NH3 when treated with water or certain alcohols, is an alternative to premade NH3 solutions or gas cylinders that can be cumbersome to use on a small scale. Gemma E. Veitch, Katy L. Bridgwood, and Steven V. Ley demonstrated the utility of Mg₃N₂ in methanol as a reagent for the direct conversion of a broad range of esters to primary amides (carboxamides). In a separate study, the researchers used Mg₃N₂ to prepare dihydropyridines via the Hantzsch condensation of ethyl acetoacetate with various aldehydes in ethanol (Org. Lett., DOI: 10.1021/ol801399w). Magnesium nitride was previously known to release ammonia in water, the researchers note, but it had not been used to generate ammonia in organic syntheses until now. The team is still exploring the scope of the method, Bridgwood says. A paper on the preparation of pyrroles will be published soon, she adds, and experiments involving pyrimidine synthesis from nitriles, nucleophilic aromatic substitution, and continuous-flow reactions are ongoing.