“…Since the number of possible changes is enormous and very large numbers have already been made and tested, it is difficult in a brief review to give an adequate picture. More detailed reviews are available on: purines and purine nucleosides; 32 pyrimidines and pyrimidine nucleosides; 33 purine nucleosides with selective antiviral activity; 3 * pyrimidine nucleosides with selective antiviral activity; 35 aranuclecsides and aranucleotides in antiviral chemotherapy; 36 aminonucleosides; 37 5-membered aza-heterocycles and their nucleosides; 38 and selectivity of anti-herpes compounds on viral and cellular DNA synthesis. 39 The volume containing the last review 39 is also a most useful overview of clinical and pharmacological aspects of herpes viruses.…”