Heterocyclic nucleosides: chemical synthesis and biological properties

Antiviral Nucleoside InhibitorsAntiviral nucleoside inhibitors are structural analogs of natural nucleosides that interfere with viral DNA or RNA synthesis. These compounds selectively target viral polymerases due to their resemblance to host nucleosides, thereby disrupting viral genome replication.Mechanism of Acyclovir ActionAcyclovir is a guanosine analog with a three-carbon acyclic side chain. It selectively targets herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2 (HSV-2),...

Nucleic acid biosynthesis is a fundamental biochemical process that produces the purine and pyrimidine nucleotides essential for DNA and RNA synthesis. This pathway maintains a balanced nucleotide pool, preventing imbalances that could jeopardize genetic integrity and cellular function. Given the crucial role of nucleotides, their synthesis is tightly regulated to ensure proper cellular homeostasis.Purine BiosynthesisThe biosynthesis of purine nucleotides begins with ribose-5-phosphate, a...

Heterocyclic amines, where the N atom is a part of an alicyclic system, are similar in basicity to alkylamines. Interestingly, the heterocyclic amine having a nitrogen atom as part of an aromatic ring has much less basicity than its corresponding alicyclic counterpart. For this reason, as presented in Figure 1, piperidine (pKb = 2.8) is significantly more basic than pyridine (pKb = 8.8).

The simplest aromatic amine is phenylamine, which contains an –NH2 functionality directly attached to an aromatic ring. The name aniline is designated for this skeleton. As shown in Figure 1, the common names of the functionalized anilines involve prefixes ortho-, meta-, and para- to indicate the substitution position. Different functionalized aniline derivatives also have notable trivial names.

Nucleic acids are the most important macromolecules for the continuity of life. They carry the cell's genetic blueprint and have instructions for its functioning. The two main types of nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
Deoxyribonucleic Acid (DNA)
DNA is the genetic material in all living organisms, ranging from single-celled bacteria to multicellular mammals. It is in the nucleus of eukaryotes and the organelles such as chloroplasts and mitochondria. In...

Bacterial pathogens depend on precise and efficient DNA replication to sustain infection. Two type II topoisomerases—DNA gyrase and topoisomerase IV—are critical to this process, as they resolve DNA supercoiling and unlink chromosomes during replication. Fluoroquinolones, synthetic derivatives of quinolones, exploit this mechanism by stabilizing the transient DNA–enzyme cleavage complex, preventing strand religation, and causing lethal double-strand breaks. These antibiotics are selectively...