Theme XVIII: Heterocycles

Purine: Structure and biological significance. Main purine bases: adenine, guanine and uric acid. Formulas, structures, tautomeric forms, derivatives.

Purine

Is called purine to the condensed nucleus pyrimidine-imidazole and is widely distributed in nature.

Purine (pyrimidine-imidazole)

Purine is tautomeric and its derivatives may be from any of its two forms. Its nitrogen atoms confer basicity.

Tautomeric forms

Derivatives

Among its derivatives are uric acid and urea, the ending product of the nitrogenous metabolism of many animals; caffeine, theobromine and theophylline; alkaloids of coffee, cocoa and tea.

          Uric acid                   Adenine                    Guanine

Other derivatives such as adenine and guanine are forming structures of nucleic acids.

The mono, di and adenosine triphosphate (AMP, ADP and ATP) are nucleotides involved as coenzymes in numerous metabolic phosphorylations, playing a key role as conveyors of chemical energy in plants and animals.

See also

Introduction to heteroclycles

Heteroclyclic compounds
Pentagonal heterocyclic compounds with one heteroatom
Pyrrole
Porphyrin. Porphyrin ring
Chlorophyll

Hexagonal heterocyclic compounds: The Pyran and Pyrimidine

Pyrimidine ring
Indole, tryptophan, indole-3-acetic acid
Structure of nucleic acids

Coffee

Cocoa

Tea