Thymine

Thymine
Names
	Preferred IUPAC name 5-Methylpyrimidine-2,4(1H,3H)-dione
	Other names 5-Methyluracil
Identifiers
CAS Number	65-71-4 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:17821 ;
ChEMBL	ChEMBL993 ;
ChemSpider	1103 ;
ECHA InfoCard	100.000.560
IUPHAR/BPS	4581;
MeSH	Thymine
PubChem CID	1135;
UNII	QR26YLT7LT ;
CompTox Dashboard (EPA)	DTXSID4052342 ;
	InChI InChI=1S/C5H6N2O2/c1-3-2-6-5(9)7-4(3)8/h2H,1H3,(H2,6,7,8,9) Key: RWQNBRDOKXIBIV-UHFFFAOYSA-N ;
	SMILES O=C1NC(=O)NC=C1C;
Properties
Chemical formula	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)
Solubility in water	3.82 g/L
Acidity (pKa)	9.7
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Thymine (/ˈθaɪmɪn/) (symbol T or Thy) is one of the four nucleobases 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]

^ 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.
^ 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.]

[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.]

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