Cytosine

Cytosine

Names
IUPAC name 4-aminopyrimidin-2(1H)-one
Other names 4-amino-1H-pyrimidine-2-one
Identifiers
CAS Number	71-30-7 Y
3D model (Jmol)	Interactive image
ChEBI	CHEBI:16040 Y
ChEMBL	ChEMBL15913 Y
ChemSpider	577 Y
ECHA InfoCard	100.000.681
KEGG	C00380 Y
MeSH	Cytosine
PubChem	597
UNII	8J337D1HZY Y
InChI InChI=1S/C4H5N3O/c5-3-1-2-6-4(8)7-3/h1-2H,(H3,5,6,7,8) Y Key: OPTASPLRGRRNAP-UHFFFAOYSA-N Y InChI=1/C4H5N3O/c5-3-1-2-6-4(8)7-3/h1-2H,(H3,5,6,7,8) Key: OPTASPLRGRRNAP-UHFFFAOYAY
SMILES c1cnc(=O)[nH]c1N
Properties
Chemical formula	C4H5N3O
Molar mass	111.10 g/mol
Density	1.55 g/cm3 (calculated)
Melting point	320 to 325 °C (608 to 617 °F; 593 to 598 K) (decomposes)
Acidity (pKa)	4.45 (secondary), 12.2 (primary)
Magnetic susceptibility (χ)	-55.8·10−6 cm3/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

Cytosine (/ˈsaɪtəˌsiːn, -ˌziːn, -ˌsɪn/;C) is one of the four main bases found in DNA and RNA, along with adenine, guanine, and thymine (uracil in RNA). It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached (an amine group at position 4 and a keto group at position 2). The nucleoside of cytosine is cytidine. In Watson-Crick base pairing, it forms three hydrogen bonds with guanine.

Cytosine was discovered and named by Albrecht Kossel and Albert Neumann in 1894 when it was hydrolyzed from calf thymus tissues. A structure was proposed in 1903, and was synthesized (and thus confirmed) in the laboratory in the same year.

In 1997 cytosine was used in an early demonstration quantum information processing when Oxford University researchers implemented the Deutsch-Jozsa algorithm on a two qubit nuclear magnetic resonance quantum computer (NMRQC).