It deliquesces in the air and melts readily on heating.
Pyrimidine, C4H4N2, itself is a water-soluble base which melts at 21° C. and possesses a narcotic smell.
6), melts at 180-181°C. The simple oxypyrimidines are obtained by the action of nitrous acid on the amino derivatives, or by heating these latter with concentrated hydrochloric acid to 180° C. They show both basic and phenolic properties and are indifferent to the action of reducing agents.
Uracil and its homologues may be obtained in many cases from the hydrouracils by the action of bromine, and subsequent elimination of the elements of hydrobromic acid; or by the condensation of aceto-acetic ester and related substances with urea, thiourea, guanidine, &c. Uracil, C4H402N2, crystallizes in colourless needles, is soluble in hot water and melts with decomposition at 335° C. Hydrouracil, C4H602N2, is obtained by the action of bromine and caustic alkalis on succinamide (H.