Metal-mediated cyanamide–hydroxyguanidine coupling

• First example of reaction between any nitrile group and any hydroxyguanidine.
• Zinc(II)-mediated coupling.
• Addition to metal-activated nitriles.
• Complexes are relevant to intermediates of the Zn(II)-catalyzed hydration of RCN.

Reaction of the cyanamides R2NCN (R = Me 2a, Et 2b) with the hydroxyguanidine OC4H8NC(NOH)NH2 (1) in the presence of zinc halides leads to [ZnX2{HNC(NR2)ONC(NH2)NC4H8O}] derived from the ZnII-mediated cyanamide–hydroxyguanidine coupling. This reaction is the first observation of interplay between any nitrile group and any hydroxyguanidine both in metal-involving and metal-free chemistry. Complexes 3a,b–5a,b rather rapidly degrade in solutions at RT, but solvates 3a,b·MeOH and 4a·MeOH are sufficiently stable in the solid state and they were characterized by IR, HRESI+-MS, solid state CP-MAS TOSS 13C NMR, and X-ray crystallography (for 3a,b). Complexes 4b and 5a,b were identified in solutions by HRESI+-MS.

The ZnII-mediated cyanamide–hydroxyguanidine coupling represents the first observation of interplay between any nitrile group and any hydroxyguanidine.Figure optionsDownload as PowerPoint slide