Antiviral drugs are a class of medicines particularly used for the treatment of
viral infections. Drugs that combat viral infections are called antiviral drugs. Viruses
are among the major pathogenic agents that cause a number of serious diseases in
humans, animals and plants. Viruses cause many diseases in humans, from self-resolving diseases to acute fatal diseases. The strategies for the development of
antiviral drugs are generally focused on two different approaches, i.e., targeting the
viruses themselves or the host cell factors. Antiviral drugs that directly target viruses
include the inhibitors of virus attachment, inhibitors of virus entry, uncoating
inhibitors, polymerase inhibitors, protease inhibitors, nucleotide reverse transcriptase,
inhibitors of nucleoside and the inhibitors of integrase. The inhibitors of protease
(ritonavir, atazanavir and darunavir), viral DNA polymerase (acyclovir, tenofovir,
valganciclovir and valacyclovir) and integrase (raltegravir) are listed among the top
200 drugs by sales during the2010. Still, there are no effective antiviral drugs available
for many viral infections. There is a couple of drugs for herpes viruses, many for
influenza and some new antiviral drugs for treating hepatitis C infection and HIV. This
chapter gives an overview of the pyrimidines and hetero annulated pyrimidines that
have been reported to be active against viral infections; identification of novel
pyrimidine leads may be used in the designing of new potent, selective and less toxic
novel therapeutic agents having promising antiviral activity. An effort has been made
to compile all the possible information regarding antiviral pyrimidines and bring them
together to make easy availability of the existing literature on the subject. The objective
of this chapter is to provide the structural and antiviral activity information as well as
methods being used for the screening of the antiviral activity and antiviral potential
IC50/ED50/CC50 values of the reported active pyrimidines are briefly discussed.
Keywords: Antiviral drugs, Antiviral pyrimidines, Inhibitory actions, Mechanisms of action.
