Calcium Dialkylamine Diazeniumdiolates: Synthesis, Stability, and Nitric Oxide Generation.

The therapeutic application of nitric oxide, an endogenous cellular signaling molecule, has been limited due to the difficulty of developing stable pro-drugs with slow kinetics of NO release. Diazeniumdiolates are valuable NO donors; however, synthetic challenges have hampered their use. O-alkylation or arylation of diazeniumdiolates form stable pro-drugs which have found application in hypertension, cancer, and as antimicrobial agents. The synthesis of sodium diazeniumdiolates has proven to be challenging due to hazardous reaction conditions (high NO concentrations, and flammable solvents), which can lead to detonation and suffered from limited scope. We have previously disclosed that synthesis of calcium diazeniumdiolate salts are a safer and more scalable alternative. Herein, we report the expanded scope of calcium diazeniumdiolates from benzylic amines, amides, and sterically bulky amines hitherto inaccessible and a comparison of their reactivity in comparison to sodium diazeniumdiolate.