On the Chemistry of the Pyrimidines

The study of the action of ferrous bicarbonate plus air on the pyrimidinesl has been continued and the chemical change in the pyrimidine ring examined in more detail. If an aqueous solution of cytosine is treated with the system ferrous sulfate plus sodium bicarbonate plus air, hydrolysis of the amino group occurs with the formation of uracil and the liberation of ammonia. Since uracil is formed from cytosine it might be assumed that in the further reaction of the system ferrous bicarbonate plus ‘air, identical results should be expected, whether cytosine or uracil were used as the starting material. That is, however, not the case because the ammonia released from cytosine influences the reaction. The subsequent course of this influence will be described later in this paper. Before the mechanism of the chemical changes in the pyrimidines, uracil and cytosine, was cleared up, it seemed as if uracil and cytosine behaved entirely differently,, since different but characteristic color reactions were obtained in each case. In our previous experiments with uracil and cytosine, we had studied the behavior of these compounds towards sodium-pentacyano-aquo ferroate (aquo salt) and had found that the two pyrimidines form penetration compounds of different colors.