Cyanamides to ureas

Ferrihydrite Conversion cyanamide to urea or dicyanamide Amberg and Vilsmeier, 1978... 

The cyanamides are active anticorrosive pigments which have a passivating action under alkaline conditions. The action of lead in anticorrosive pigments is discussed in Section 5.2.10.1. Heavy metal oxides, especially of iron and manganese, catalyze the conversion of cyanamide to urea even below 20 °C [5.126] ... 

In addition to the physiological reaction, the reversible hydration of CO2 to bicarbonate (reaction 1, Scheme 1), CAs catalyze a variety of other reactions, such as the hydration of cyanate to carbamic acid, or of cyanamide to urea (reactions 2 and 3) the aldehyde hydration to gem-diols (reaction 4) the hydrolysis of carboxylic, or sulfonic (reactions 5, 6), as well as other less investigated hydrolytic processes, such as those described by equations 7-10 in Scheme 1 (Supuran et al., 1997 Supuran and Scozzafava, 2000b Guerri et al., 2000). It should be mentioned that the previously reported phosphatase activity of CA III was recently proved to be an artefact (EGm et al., 2000). It is unclear at this moment whether CA catalyzed reactions other than the CO2 hydration has physiological significance. 

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