Thymine

For the B vitamin whose name sounds and looks similar, see Thiamine.
Not to be confused with thymidine.
Thymine
Names
Preferred IUPAC name
5-Methylpyrimidine-2,4(1H,3H)-dione
Other names
5-Methyluracil
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.000.560 Edit this at Wikidata
MeSH Thymine
UNII
  • InChI=1S/C5H6N2O2/c1-3-2-6-5(9)7-4(3)8/h2H,1H3,(H2,6,7,8,9) checkY
    Key: RWQNBRDOKXIBIV-UHFFFAOYSA-N checkY
  • O=C1NC(=O)NC=C1C
Properties
C5H6N2O2
Molar mass 126.115 g·mol−1
Density 1.223 g cm−3 (calculated)
Melting point 316 to 317 °C (601 to 603 °F; 589 to 590 K)
Boiling point 335 °C (635 °F; 608 K) (decomposes)
3.82 g/L[1]
Acidity (pKa) 9.7
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Thymine (/ˈθaɪmɪn/) (symbol T or Thy) is one of the four nucleotide bases in the nucleic acid of DNA that are represented by the letters G–C–A–T. The others are adenine, guanine, and cytosine. Thymine is also known as 5-methyluracil, a pyrimidine nucleobase. In RNA, thymine is replaced by the nucleobase uracil. Thymine was first isolated in 1893 by Albrecht Kossel and Albert Neumann from calf thymus glands, hence its name.[2]

  1. ^ Dannenfelser, R.-M.; Yalkowsky, S.H. (December 1991). "Data base of aqueous solubility for organic non-electrolytes". Science of the Total Environment. 109 (C): 625–628. Bibcode:1991ScTEn.109..625D. doi:10.1016/0048-9697(91)90214-Y. Retrieved 2021-11-14.
  2. ^ Albrecht, Kossel; Neumann, Albert (Oct–Dec 1893). "Ueber das Thymin, ein Spaltungsproduct der Nucleïnsäure" [On thymine, a cleavage product of nucleic acid]. Berichte der Deutschen Chemischen Gesellschaft. 26 (3): 2753–2756. doi:10.1002/cber.18930260379. Retrieved 2021-11-14. p. 2754: Wir bezeichnen diese Substanz als Thymin. [We designate this substance as thymine.]