Cytosine
C₄H₅N₃O·111.102 g/mol·Biochemical·CID 597
NucleobaseEssential
A pyrimidine nucleobase that pairs with guanine via three hydrogen bonds in DNA and RNA. Deamination of cytosine produces uracil — one of the most common forms of DNA damage, repaired by uracil-DNA glycosylase.
IUPAC: 6-amino-1H-pyrimidin-2-one
Also known as: 71-30-7, 4-Amino-2-hydroxypyrimidine, 4-aminopyrimidin-2(1H)-one, Cytosinimine, 2(1H)-Pyrimidinone, 4-amino- (+14 more)
Molecular Structure
Molecular Propertiesmass · H-bonds · stereo
Molecular Weight
111.100g/mol
Exact Mass
111.043262Da
Monoisotopic Mass
111.043262Da
XLogP
-1.7
Polar Surface Area
67.5Ų
Complexity
170
Formal Charge
0
H-Bond Donors
2
H-Bond Acceptors
2
Rotatable Bonds
0
Heavy Atoms
8
Stereo Centers
0
Bond Stereo
0
Drug-Likeness (Lipinski's Rule of Five)
✓ 111.1 g/mol
MW ≤ 500
✓ -1.7
LogP ≤ 5
✓ 2
H-bond donors ≤ 5
✓ 2
H-bond acceptors ≤ 10
Passes all rules — good oral bioavailability predicted
GHS Hazard Classification
Warning
Hazards
H315Causes skin irritationH319Causes serious eye irritationH335May cause respiratory irritation
Source: PubChem GHS Classification. Always consult the SDS for handling.
Constituent Elements
Isomers8 compounds with formula C₄H₅N₃O
4-amino-1,3-diazabicyclo[3.1.0]hex-3-en-2-one
CID 68791 · 111.1 g/mol
1H-imidazole-5-carboxamide
CID 152917 · 111.1 g/mol
2-amino-1H-pyrimidin-6-one
CID 66950 · 111.1 g/mol
4-amino-1H-pyrimidin-6-one
CID 135431272 · 111.1 g/mol
2-cyanoaziridine-1-carboxamide
CID 41854 · 111.1 g/mol
1-methyltriazole-4-carbaldehyde
CID 14313438 · 111.1 g/mol
3-methoxy-1,2,4-triazine
CID 286862 · 111.1 g/mol
2-aminopyrimidin-5-ol
CID 17750388 · 111.1 g/mol