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] In particular, it is used as a nucleobase of hachimoji RNA.[2]

Isocytosine
Names
Preferred IUPAC name
2-Amino-3H-pyrimidin-4-one
Other names
2-Aminouracil
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.003.266 Edit this at Wikidata
  • InChI=1S/C4H5N3O/c5-4-6-2-1-3(8)7-4/h1-2H,(H3,5,6,7,8) checkY
    Key: XQCZBXHVTFVIFE-UHFFFAOYSA-N checkY
  • InChI=1/C4H5N3O/c5-4-6-2-1-3(8)7-4/h1-2H,(H3,5,6,7,8)
    Key: XQCZBXHVTFVIFE-UHFFFAOYAD
  • O=C1/C=C\N=C(\N)N1
Properties
C4H5N3O
Molar mass 111.104 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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Isoguanine-Isocytosine-base-pair

It can be synthesized from guanidine and malic acid.[3]

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.[4]

Tautomerism of isocytosine

References

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  1. ^ "Isocytosine". Molecule of the Week. American Chemical Society. Retrieved November 1, 2012.
  2. ^ Hoshika, Shuichi; et al. (22 February 2019). "Hachimoji DNA and RNA: A genetic system with eight building blocks". Science. 363 (6429): 884–887. doi:10.1126/science.aat0971. PMC 6413494. PMID 30792304.
  3. ^ William T. Caldwell , Harry B. Kime (1940). "A New Synthesis of Isocytosine". J. Am. Chem. Soc. 62 (9): 2365–2365. doi:10.1021/ja01866a028.
  4. ^ "Isocytosine". Sigma-Aldrich. Retrieved November 1, 2012.