Editing Thymine (section)

==Synthesis==
===Laboratory synthesis===
Thymine was first prepared by hydrolysis of the corresponding [[nucleoside]] obtained from natural sources. Interest in its direct chemical synthesis began in the early 1900s: [[Emil Fischer]] published a method starting from [[urea]] but a more practical synthesis used methylisothiourea in a [[condensation reaction]] with ethyl formyl propionate, followed by hydrolysis of the pyrimidine intermediate:<ref>{{cite journal |last1=Wheeler |first1=H.I. |last2=Merriam |first2=H.F. |year=1903 |title=On some condensation products of the pseudothioureas: synthesis of uracil, thymine, and similar compounds. |journal=American Chemical Journal |volume=29 |issue=5 |pages=478–492 |url=https://babel.hathitrust.org/cgi/pt?id=uc2.ark:/13960/t72v2dx94&view=1up&seq=17}}</ref>
:[[File:Thymine synthesis (1903).svg|600px|class=skin-invert-image]]
Many other preparative methods have been developed, including optimised conditions so that urea can be used directly in the reaction shown above, preferably with methyl formyl propionate.<ref>{{cite journal |doi=10.1007/s00706-013-1128-y |title=An environmentally benign approach to the synthesis of thymine via hydroformylation of methyl acrylate |year=2014 |last1=Guo |first1=Xianghai |last2=Shen |first2=Jiaxiang |journal=Monatshefte für Chemie - Chemical Monthly |volume=145 |issue=4 |pages=657–661 |s2cid=97367180 }}</ref>