Diaminomethyleneaminocarbonyldinitromethane, formed during the preparation of 2-amino-6-chloro-5-nitro-4(3H)-pyrimidinone by nitration of 2-amino-6-chloro-4(3H)-pyrimidinone

Difficulties in the nitration of 2-amino-6-chloro-4(3H)-pyrimidinone to give the widely used heterocyclic precursor 2-amino-6-chloro-5-nitro-4(3H)-pyrimidinone are shown to be due to formation of an unusual open-chain gem-dinitro compound, identified as diaminomethyleneaminocarbonyldinitromethane. The latter is also formed by the nitration of 2-amino-4,6(3H,5H)-pyrimidinedione. It decomposes with loss of carbon dioxide in dimethyl sulfoxide, or in aqueous potassium hydroxide, to give guanidine and dinitromethane.