CHAPTER 3 



Chemistry of Purines and Pyrimidines 

 AARON BENDICH 



I. Introduction 81 



1 . Historical 81 



2. Nomenclature 82 



3. Occurrence and Distribution 84 



a. Purines and Pyrimidines of Nucleic Acid Origin 84 



h. Purines and Pyrimidines in Other Biological Sources 03 



c. Purine and Pj-^rimidine Derivatives and Analogues of Biological im- 

 portance 101 



II. General Properties of Purines and Pyrimidines 107 



1. Physical Properties 107 



a. Solubility; Distribution Studies; Chromatography 107 



b. Criteria of Purity and Identity; the Value of Ultraviolet Absorption 

 Spectra; Ionization; Tautomerism; the Value of the Isost)estic Point . 110 



2. Chemical Properties 110 

 a. Stability Towards Acid and Alkali ; Transformations; Nitrous Acid . 1 17 

 1). Action of Reducing Agents; Polarographic Behavior 119 



c. Action of Oxidizing Agents and Ultiaviolot Light 120 



d. Color Tests 123 



e. Salt Formation 124 



III. Synthetic Methods 125 



1. General Methods for Pyrimidines and for the Introduction of Isotopes . 125 



a. Transformations; the Value of Halogen and Mercai)to Derivatives . . 126 



b. Newer Methods 129 



2. General Methods for Purines and for the Introduction of Isotopes . . . . 130 



a. From Purines 130 



b. From I'yrimidines 131 



c. From Imidazoles 134 



Addendum 135 



General References 136 



I. Introduction 



1. Historical 



Pyrimidines and purines are intimately associated with all the living 

 systems which have thus far been studied, and have been found, as Rivers 

 put it,^ even "... in the twilight zone between the living and the non- 



^ T. M. Rivers, "Viral and Rickettsial Infections of Man," 2nd ed., p. 5. Lippincott, 

 Philadelphia, 1952. 



81 



