COMPARED DEPROTONATIONS OF URACIL, THYMIN , ISOBARBITURIC ACID, ISOOROTIC ACID AND 5-HALOGENO-URACIL IN A ACID IN A WIDE PH RANGE

Successive deprotonations of 5-hydroxy-2, 4-(1H, 3H)pyrimidinedione (i sobarbituric acid), 5-methyl-2,4-(1H, 3H)pyrimidinedione (thymin), 5-c arboxy-2, 4-(1H, 3H)pyrimidinedione (isoorotic acid), 5-bromo-2, 4-(1H , 3H)pyrimidinedione (5-bromouracil), and 5-iodo-2, 4-(1H, 3H)pyrimidi nedione (5-iodouracil), are displayed in a wide pH range (2 < pH < 16) . The conditional stability constants and the molar absorbance of each protonated form have been determined by simultaneous protometric and spectrometric UV measurements. A rapid qualitative and quantitative an alysis can be performed for mixed solutions containing two compounds.