Performing organic chemistry with inorganic compounds: electrophilic reactivity of selected nitrosyl complexes

The inorganic nitrosyl (NO(+)) complexes [Fe(CN) 5NO](2-), [Ru(bpy)2(NO)Cl](2+), and [IrCl 5(NO)](-) are useful reagents for the nitrosation of a variety of organic compounds, ranging from amines to the relatively inert alkenes. Regarding [IrCl 5(NO)](-), its high electrophilicity and inertness define it as a unique reagent and provide a powerful synthetic route for the isolation and stabilization of coordinated nitroso compounds that are unstable in free form, such as S-nitrosothiols and primary nitrosamines. Related to the high electrophilicity of [IrCl 5(NO)](-), an unusual behavior is described for its PPh 4(+) salt in the solid state, showing an electronic distribution represented by Ir(IV)-NO(*) instead of Ir (III)-NO(+) (as for the K(+) and Na(+) salts).

Amine nitrosation by sodium nitroprusside

Nitrosamine formation from the reaction of nitroprusside with morpholine was found to be a light-dependent reaction. Maximum nitrosation occurred when the reactants were exposed to UV light (lambda = 275-300 nm). However, considerable nitrosation also occurred with light in the visible spectrum up to 500 nm. No significant nitrosamine formation was observed when the reactants were kept in the dark. Data concerning the effects of other physical and chemical factors such as pH, temperature and reactant concentration on the reaction between morpholine and sodium nitroprusside are also presented.

Inactivation of angiotensin converting enzyme by sodium nitroprusside

Angiotensin I converting enzyme is rapidly inactivated by sodium nitroprusside and that inactivation is suppressed in the presence of chloride ion and by the presence of L-alanyl-L-proline or glycyl-L-tryptophan, which are both competitive inhibitors of its catalytic activity. The inactivation by sodium nitroprusside appears to result from the modification of an unusually reactive lysine residue in or near the active site.