Title: Guanine
CAS Registry Number: 73-40-5
CAS Name: 2-Amino-1,7-dihydro-6H-purin-6-one
Additional Names: 2-aminohypoxanthine
Molecular Formula: C5H5N5O
Molecular Weight: 151.13
Percent Composition: C 39.74%, H 3.33%, N 46.34%, O 10.59%
Literature References: Constituent of nucleic acids; widespread in animal and plant kingdom. First isolated from guano. Syntheses: Fisher, Ber. 30, 2226 (1897); Traube, ibid. 33, 1371 (1900); DE 134984 (1903); DE 158591 (1903); DE 162336 (1904). Prepn of 15N-isotopic guanine following Traube's synthesis: Plentl, Schoenheimer, J. Biol. Chem. 153, 203 (1944). Several desmotropic forms. Crystal structure of hydrochloride monohydrate: Broomhead, Acta Crystallogr. 4, 92 (1951). Reviews: Shapiro, Prog. Nucleic Acid Res. Mol. Biol. 8, 73-112 (1968); 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: Usually amorphous. Small rhombic crystals by slow evaporation of aq soln contg large excess of NH3. Dec above 360° with partial sublimation. uv max (pH 6.2): 246, 275 nm (e ´ 10-3 10.7, 8.1). Freely sol in ammonia water, aq KOH solns, dil acids; sparingly sol in alcohol, ether. Almost insol in water. pKb 3.22; pKa 9.92, detd at 40°. Many compds with acids, bases and metals have been prepared.
pKa: pKb 3.22; pKa 9.92, detd at 40°
Absorption maximum: uv max (pH 6.2): 246, 275 nm (e ´ 10-3 10.7, 8.1)
Derivative Type: Hydrochloride monohydrate
Molecular Formula: C5H5N5O.HCl.H2O
Molecular Weight: 205.60
Percent Composition: C 29.21%, H 3.92%, N 34.06%, O 15.56%, Cl 17.24%
Properties: Cryst powder. Loses H2O at 100°, HCl at 200°. Practically insol in water, alcohol, ether; sol in acidulated water.
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