Valliappan Kannappan

🧭 The Molecular Grammar of Medicines: Isomerism, Chirality, and Stereochemical Relationships Explained

Leave a Comment / Chiral science, Chirality, Drug stereochemistry, Stereochemistry / By / , , , , , / November 7, 2025

“Where molecules speak, stereochemistry gives them meaning“ In pharmaceuticals, structure is language — and stereochemistry is its grammar. The way atoms arrange in 3D space shapes how drugs work, how they are regulated, and how safe they are. This Chiralpedia tutorial simplifies the molecular “grammar” behind drug behavior and innovation. When Structure Speaks Every drug molecule has a story written in its structure. Two compounds may share the same formula yet act entirely differently due …

🧭 The Molecular Grammar of Medicines: Isomerism, Chirality, and Stereochemical Relationships Explained Read More »

Part 10: Stereochemistry in Pharmaceutical Sciences – Current Trends and Future Directions

Leave a Comment / Stereochemistry / By / , , / October 6, 2025

“Beyond today – emerging trends shaping the future of stereochemistry in pharma” Introduction The landscape of stereochemistry in pharmaceutical sciences continues to evolve with scientific and technological advances. This final part looks at emerging trends and future challenges. These include: – New developments in asymmetric catalysis, such as organocatalysts (MacMillan/List catalysts) that have expanded the toolkit for chiral synthesis, and the 2021 Nobel recognition of this field – implying more green and metal-free asymmetric processes …

Part 10: Stereochemistry in Pharmaceutical Sciences – Current Trends and Future Directions Read More »

Part 9: Stereochemistry in Drug Discovery and Development

Leave a Comment / Stereochemistry / By / , , / October 3, 2025

“From hit to lead to medicine – where stereochemistry shapes every stage of discovery” Introduction Stereochemistry is not only crucial in the final stages of drug production – it plays a significant role right from the discovery and lead optimization phases. In this part, we consider how medicinal chemists account for chirality when designing compounds and how structure-activity relationships (SAR) can depend on stereochemistry. We also look at how screening libraries incorporate stereochemical diversity, and …

Part 9: Stereochemistry in Drug Discovery and Development Read More »

Part 8: Stereochemistry in Biologics and Natural Products

Leave a Comment / Stereochemistry / By / , / October 3, 2025

“Nature’s stereochemists – chirality in biologics, peptides, and natural products” Introduction Stereochemistry is inherent in biological macromolecules and natural products. This part explores chirality beyond small synthetic drugs – specifically, in biologics (peptides, proteins, nucleic acids) and in natural product-derived drugs. We examine how nature’s biosynthetic machinery imparts stereochemistry with high fidelity (e.g., enzymes produce single enantiomers of amino acids, sugars, complex polyketides). We discuss examples of drugs that are derived from natural chirality (like …

Part 8: Stereochemistry in Biologics and Natural Products Read More »

Part 7: Analytical Techniques for Stereochemistry

Leave a Comment / Stereochemistry / By / , , , / October 2, 2025

“Measuring handedness – tools and techniques that bring chirality into focus” Introduction Ensuring the correct stereochemistry and measuring stereochemical purity is a crucial aspect of pharmaceutical quality control and research. This part covers the major analytical techniques used to distinguish and quantify enantiomers and diastereomers in drug substances and products. Key techniques include: We’ll discuss how these techniques are applied in practice: e.g., during process development, a chiral HPLC method is developed to monitor enantiomeric …

Part 7: Analytical Techniques for Stereochemistry Read More »

Part 6: Resolution of Enantiomers

Leave a Comment / Stereochemistry / By / , , / October 2, 2025

“Separating the inseparable: how chemists resolve mirror-image molecules.” Introduction Despite advances in asymmetric synthesis (Part 5), sometimes we still end up with a racemic mixture of enantiomers. When direct stereoselective routes are impractical, chemists must separate the enantiomers – a process known as resolution. This part examines classical and modern methods for resolving enantiomers, their pros and cons, and how they are applied in pharmaceutical contexts. We will cover: We’ll also discuss the racemic mixture …

Part 6: Resolution of Enantiomers Read More »

Part 5: Stereoselective and Stereospecific Synthesis

Leave a Comment / Stereochemistry / By / , , / September 10, 2025

“Crafting molecules with precision – the art of stereochemical synthesis” Introduction Having seen why the correct stereochemistry is crucial for drug efficacy and safety, the next challenge is how to obtain the desired stereoisomer. This part covers strategies and methods in stereoselective and stereospecific synthesis. We clarify the terminology: a stereoselective reaction preferentially yields one stereoisomer over others (e.g., one enantiomer or one diastereomer is favored), whereas a stereospecific reaction produces different stereoisomeric products from …

Part 5: Stereoselective and Stereospecific Synthesis Read More »

Part 4: Stereochemistry in Drug Action and Pharmacology

Leave a Comment / Stereochemistry / By / , / October 2, 2025

“Why one enantiomer heals while the other may harm – the pharmacology of chirality” Introduction Chirality doesn’t just influence drug properties in theory – it has very real consequences in pharmacology. In this section, we explore how stereochemistry affects drug action at multiple levels: pharmacodynamics (drug-receptor interactions) and pharmacokinetics (absorption, distribution, metabolism, excretion). We will define terms like eutomer (the more active enantiomer) and distomer (the less active one) and introduce the concept of the …

Part 4: Stereochemistry in Drug Action and Pharmacology Read More »

Part 3: Nomenclature and Configuration

Leave a Comment / Stereochemistry / By / , , / September 4, 2025

“Decoding the rules: how chemists name and navigate molecular twists.” Introduction Correctly describing the stereochemistry of a molecule is as important as understanding it. In this part, we focus on the Cahn–Ingold–Prelog (CIP) system, which provides the rules for unambiguous assignment of absolute configuration at stereocenters (R/S) and for double bond geometry (E/Z) system. We will outline the CIP priority rules step-by-step and demonstrate how to apply them to pharmaceutical molecules. Additionally, we will discuss …

Part 3: Nomenclature and Configuration Read More »

Part 2: Fundamental Concepts of Chirality

Leave a Comment / Stereochemistry / By / / October 2, 2025

“From left- and right-handedness to life’s molecular signatures—chirality explained” Introduction Building on the overview of chirality, this section delves into core concepts: symmetry elements in molecules, the definitions of enantiomers and diastereomers, and the phenomenon of optical activity. Understanding these fundamentals is essential for grasping how stereochemistry manifests and is measured. We will also explore how chirality is quantified via optical rotation and how instruments like polarimeters help distinguish enantiomers. By the end of this …

Part 2: Fundamental Concepts of Chirality Read More »