CAS No 66-22-8 , 1H-pyrimidine-2,4-dione

Title: Uracil
CAS Registry Number: 66-22-8
CAS Name: 2,4(1H,3H)-Pyrimidinedione
Synonyms: 2,4-dioxopyrimidine; 2,4-pyrimidinediol; 4-hydroxy-2(1H)-pyrimidinone; 2-hydroxy-4(1H)-pyrimidinone; 2-hydroxy-4(3H)-pyrimidinone
Molecular Formula: C4H4N2O2
Molecular Weight: 112.09
Percent Composition: C 42.86%, H 3.60%, N 24.99%, O 28.55%
Literature References: Obtained by hydrolysis of nucleic acids, cf. Levene, Bass, Nucleic Acids (New York, 1931). Alternate routes of formation: Johnson, J. Am. Chem. Soc. 63, 263 (1941); Fox, Harada, Science 133, 1923 (1961); Takemoto, Yamamoto, Synthesis 1971, 154. Several desmotropic forms. Crystal structure: Stewart, Acta Crystallogr. 23, 1102 (1967). Review: Ts'o "Bases, Nucleosides and Nucleotides" in Basic Principles in Nucleic Acid Chemistry vol. 1, P. O. P Ts'o, Ed. (Academic Press, New York, 1974) pp 453-584.
Properties: Needles from water, mp 335° with effervescence. uv max (pH 7.0): 202.5, 259.5 nm (e ′ 10-3 9.2, 8.2). Freely sol in hot water; sparingly in cold water (100 parts of water at 25° dissolves 0.358 part of uracil). Almost insol in alc, ether; sol in ammonia water and in other alkalies. pK = 9.45.
Melting point: mp 335° with effervescence
pKa: pK = 9.45
Absorption maximum: uv max (pH 7.0): 202.5, 259.5 nm (e ′ 10-3 9.2, 8.2)
Use: In biochemical research.