Thymine structural formula

The three pyrimidine bases are uracil, thymine, and cytosine, usually abbreviated U, T, and C. Adenine (A) and guanine (G) are the two purine bases. Adenine, guanine, and cytosine are found in both DNA and RNA, but uracil is ordinarily found only in RNA, and thymine only in DNA. Structural formulas of the five bases are given in I Figure 11.3. 

Write the structural formula for the nucleotide thymidine 5 -monophosphate. The base component is thymine. 

Section 17.81). This is the form normally present in DNA, and, as we have seen, it pairs specifically with cytosine. If guanine tautomerizes (see Section 18.2) to the lactim form, it pairs with thymine instead. Write structural formulas showing the hydrogen bonds in this abnormal base pair. 

Draw a structural formula for the /3-A/-glycoside formed between (a) D-ribofuranose and thymine and (b) D-ribofuranose and guanine. Label the anomeric carbon and the AZ-glycosidic bond. (See Example 17.5)... 

Following are structural formulas for cytosine and thymine. Draw two additional tautomeric forms for cytosine and three additional tautomeric forms for thymine. 

Five organic bases (amines) are most often found in nucleotides. The bases are adenine, guanine, cytosine, uracil, and thymine. They link to the sugars through the indicated nitrogen (in color) in each of the following structural formulas ... 

The nucleic acids obtained from nucleoproteins are of unknown constitution, but their dissociation-products are fairly well known. They yield on hydrolysis phosphoric acid, pentoses, and derivatives of pyrimidine and of purine (415). It is beyond the scope of this book to discuss adequately the structure of the derivatives of pyrimidine and purine which are obtained from the nucleic acids. The graphic formulas of the derivatives which have been isolated are given here for reference. Uracil, cytosine, and thymine are derivatives of pyrimidine —... 

The nitrogen bases found in DNA comprise the two purines adenine and guanine and the two pyrimidines thymine and cytosine in the formulas shown in Figure 15-20 the asterisk indicates the hydrogen atom that is replaced by the carbon atom of the sugar ring in DNA, and the double bonds correspond to only one of the several valence-bond structures for each molecule. The molecules are planar, because each of the bonds in the purine and pyrimidine rings has some double-bond character. 

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