Question

Cytosine, uracil and guanine have tautomeric forms with aromatic hydroxyl groups. Draw these tautomeric forms.

Short answer

Tautomers of cytosine:

Tautomers of guanine:

Tautomers of Uracil:

Step-by-step solution

Explanation:

Tautomerism is a phenomenon where a single chemical compound tends to exist in two or more interconvertible structures which are different in terms of the relative position of one atomic nucleus, generally the hydrogen. Guanine and cytosine have both amino and carbonyl groups, thus they can exhibit both amino-imino and keto-enol, whereas uracil has lactam and lactim tautomers.

Tautomers of cytosine:

Tautomers of cytosine:

Tautomers of guanine:                                                          

Tautomers of guanine:

Tautomers of Uracil:                                                                                                                          

Tautomers of Uracil: