Isocytosine

Isocytosine

Names
IUPAC name 2-Amino-3H-pyrimidin-4-one
Other names 2-Aminouracil
Identifiers
CAS Number	108-53-2
ChEBI	CHEBI:55502
ChEMBL	ChEMBL56260
ChemSpider	60309
Jmol interactive 3D	Image
PubChem	66950
InChI InChI=1S/C4H5N3O/c5-4-6-2-1-3(8)7-4/h1-2H,(H3,5,6,7,8) Key: XQCZBXHVTFVIFE-UHFFFAOYSA-N InChI=1/C4H5N3O/c5-4-6-2-1-3(8)7-4/h1-2H,(H3,5,6,7,8) Key: XQCZBXHVTFVIFE-UHFFFAOYAD
SMILES O=C1/C=C\N=C(\N)N1
Properties
Chemical formula	C4H5N3O
Molar mass	111.10 g·mol^−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Isocytosine or 2-aminouracil is a pyrimidine base that is an isomer of cytosine. It is used in combination with isoguanine in studies of unnatural nucleic acid analogues of the normal base pairs in DNA.^[1]

Isoguanine-Isocytosine-base-pair

It can be synthesized from guanidine and malic acid.^[2]

Synthesis of isocytosine from malic acid

It is also used in physical chemical studies involving metal complex binding, hydrogen bonding, and tautomerism and proton transfer effects in nucleobases.^[3]

Tautomerism of isocytosine

References

1. "Isocytosine". Molecule of the Week. American Chemical Society. Retrieved November 1, 2012.
2. William T. Caldwell , Harry B. Kime (1940). "A New Synthesis of Isocytosine". J. Am. Chem. Soc. 62 (9): 2365–2365. doi:10.1021/ja01866a028.
3. "Isocytosine". Sigma-Aldrich. Retrieved November 1, 2012.