Cytosine

Cytosine
Names
Preferred IUPAC name
4-Aminopyrimidin-2(1H)-one
Other names
4-Amino-1H-pyrimidine-2-one
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.000.681 Edit this at Wikidata
KEGG
MeSH Cytosine
UNII
  • InChI=1S/C4H5N3O/c5-3-1-2-6-4(8)7-3/h1-2H,(H3,5,6,7,8) checkY
    Key: OPTASPLRGRRNAP-UHFFFAOYSA-N checkY
  • InChI=1/C4H5N3O/c5-3-1-2-6-4(8)7-3/h1-2H,(H3,5,6,7,8)
    Key: OPTASPLRGRRNAP-UHFFFAOYAY
  • O=C1Nccc(N)n1
Properties
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)[1]
-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).
checkY verify (what is checkY☒N ?)

Cytosine (/ˈstəˌsn, -ˌzn, -ˌsɪn/[2][3]) (symbol C or Cyt) is one of the four nucleotide 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.

  1. ^ Dawson, R.M.C.; et al. (1959). Data for Biochemical Research. Oxford: Clarendon Press.
  2. ^ "Cytosine". Dictionary.com Unabridged (Online). n.d.
  3. ^ "Cytosine". Merriam-Webster.com Dictionary. Merriam-Webster.