1-Methylcytosine
{{short description|Chemical compound}}
{{chembox
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| ImageFile=1-Methylcytosine.svg
| ImageSize=
| PIN=4-Amino-1-methylpyrimidin-2(1H)-one
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|Section1={{Chembox Identifiers
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 71474
| KEGG_Ref = {{keggcite|correct|kegg}}
| KEGG =
| InChI = 1S/C5H7N3O/c1-8-3-2-4(6)7-5(8)9/h2-3H,1H3,(H2,6,7,9)
| InChIKey = HWPZZUQOWRWFDB-UHFFFAOYSA-N
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C5H7N3O/c1-8-3-2-4(6)7-5(8)9/h2-3H,1H3,(H2,6,7,9)
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = HWPZZUQOWRWFDB-UHFFFAOYSA-N
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo=1122-47-0
| PubChem=79143
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 1J54NE82RV
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 39624
| ChEMBL = 500883
| SMILES = CN1C=CC(=NC1=O)N
| MeSHName=1-Methylcytosine
}}
|Section2={{Chembox Properties
| C=5 | H=7 | N=3 | O=1
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1-Methylcytosine is a methylated form of the DNA base cytosine.
In 1-methylcytosine, a methyl group is attached to the 1st atom in the 6-atom ring. This methyl group distinguishes 1-methylcytosine from cytosine.
History
Miriam Rossi worked on the refinement of 1-methylcytosine.{{Cite journal|last1=Kistenmacher|first1=T. J.|last2=Rossi|first2=M.|date=1977-12-15|title=1-Methylcytosine: a refinement|journal=Acta Crystallographica Section B|volume=33|issue=12|pages=3962–3965|doi=10.1107/S0567740877012618|bibcode=1977AcCrB..33.3962R |issn=0567-7408}}
1-Methylcytosine is used as a nucleobase of hachimoji DNA, in which it pairs with isoguanine.{{cite journal|last=Hoshika|first=Shuichi|display-authors=etal|date=22 February 2019|title=Hachimoji DNA and RNA: A genetic system with eight building blocks |journal=Science|volume=363|issue=6429|pages=884–887|doi=10.1126/science.aat0971|pmid=30792304|pmc=6413494|bibcode=2019Sci...363..884H }}