PHD
  1. Inorganic chemistry  1.1. Coordination chemistry  1.1.1. Ligand field theory  1.1.2. Crystal field theory  1.1.3. Molecular Orbital Theory for Coordination Compounds  1.1.4. Stability of Coordination Compounds  1.1.5. Electronic spectra of coordination compounds  1.1.6. Isomerism in Coordination Compounds  1.1.7. Kinetics and mechanism of coordination reactions  1.2. Organometallic Chemistry  1.2.1. Metal Carbonyls  1.2.2. Metal alkyl and aryl  1.2.3. Fischer and Schrock carbonaceans  1.2.4. Oxidative Addition and Reductive Elimination  1.2.5. Metal Hydrides  1.2.6. Catalysis by organometallic compounds  1.2.7. Metallocenes and Sandwich Complexes  1.2.8. CH activation  1.3. Solid state chemistry  1.3.1. Crystal structures and lattices  1.3.2. Band theory and electrical properties  1.3.3. Defects in the crystal  1.3.4. Synthesis of solid state materials  1.3.5. Magnetic and optical properties of solids  1.3.6. Superconductivity  1.3.7. Solid state ionics  1.4. Bio-inorganic chemistry  1.4.1. Metalloproteins and enzymes  1.4.2. Metal ion transport and storage  1.4.3. The role of metals in medicine  1.4.4. Bioinspired catalysis  1.4.5. Metal–DNA interactions  1.4.6. Metal Complexes in Medical Science  1.5. Lanthanides and Actinides  1.5.1. Electronic configuration and oxidation states in lanthanides and actinides  1.5.2. Spectral and Magnetic Properties in Lanthanides and Actinides  1.5.3. Separation and Extraction of Lanthanides and Actinides  1.5.4. Coordination chemistry of f-block elements  1.6. Main Group Chemistry  1.6.1. Chemistry of boron compounds  1.6.2. Chemistry of Silicon and Germanium Compounds  1.6.3. Chemistry of Phosphorus and Sulfur Compounds  1.6.4. Organosilicon chemistry  1.6.5. Noble Gas Chemistry
  2. Organic chemistry  2.1. Reaction mechanism  2.1.1. Nucleophilic substitution reactions  2.1.2. Electrophilic addition and substitution reactions  2.1.3. Elimination reactions  2.1.4. Rearrangement reactions  2.1.5. Radical reactions  2.1.6. Pericyclic Reactions  2.1.7. Photochemical reactions  2.2. Stereoscopic  2.2.1. Chirality and optical activity  2.2.2. Structural analysis  2.2.3. Stereoelectronic effects  2.2.4. Asymmetric synthesis  2.2.5. Dynamic Stereochemistry  2.3. Organometallic Chemistry in Organic Synthesis  2.3.1. Organolithium and organomagnesium reagents  2.3.2. Transition metal catalyzed coupling reactions  2.3.3. Palladium-catalyzed reactions  2.3.4. Olefin Metathesis  2.3.5. Gold and silver catalysis  2.4. Natural products chemistry  2.4.1. Alkaloids and terpenoids  2.4.2. Steroids and Flavonoids  2.4.3. Total synthesis of natural products  2.4.4. Biosynthesis of natural products  2.5. Supramolecular Chemistry  2.5.1. Host-Guest Chemistry  2.5.2. Self-assembly and molecular recognition  2.5.3. Supramolecular Catalysis  2.5.4. Molecular Machines
  3. Physical Chemistry  3.1. Thermodynamics  3.1.1. Laws of Thermodynamics  3.1.2. Chemical Potential and Equilibrium  3.1.3. Statistical thermodynamics  3.1.4. Non-equilibrium thermodynamics  3.2. Quantum Chemistry  3.2.1. Schrödinger equation and its applications  3.2.2. Molecular orbital theory  3.2.3. Density functional theory  3.2.4. Post-Hartree–Fock methods  3.3. Chemical kinetics  3.3.1. Reaction rate theory  3.3.2. Mechanism and rate laws  3.3.3. Catalysis and enzyme kinetics  3.3.4. Reaction dynamics  3.4. Spectroscopy and molecular structure  3.4.1. Infrared Spectroscopy  3.4.2. UV-visible spectroscopy  3.4.3. Nuclear Magnetic Resonance Spectroscopy  3.4.4. Mass Spectrometry  3.4.5. Raman Spectroscopy  3.5. Surface and Colloid Chemistry  3.5.1. Absorption and Catalysis  3.5.2. Surfactants and micelles  3.5.3. Colloidal Stability  3.5.4. Nanomaterials and Interfaces
  4. Analytical chemistry  4.1. Chromatography  4.1.1. Gas Chromatography  4.1.2. High Performance Liquid Chromatography  4.1.3. Thin Layer Chromatography  4.1.4. Ion Chromatography  4.2. Electroanalytical techniques  4.2.1. Voltammetry and Polarography  4.2.2. Conductometry and potentiometry  4.2.3. Colometry  4.3. Spectroscopic Methods  4.3.1. Atomic absorption spectroscopy  4.3.2. Fluorescence Spectroscopy  4.3.3. X-ray diffraction  4.3.4. Electron paramagnetic resonance spectroscopy  4.4. Chemometrics  4.4.1. Data processing and statistical methods  4.4.2. Multidisciplinary analysis  4.4.3. Machine Learning in Analytical Chemistry
  5. Theoretical and Computational Chemistry  5.1. Molecular dynamics simulation  5.2. Quantum chemistry methods  5.3. Computational drug design  5.4. Machine Learning in Chemistry  5.5. Ab initio molecular dynamics
  6. Biophysics and Medicinal Chemistry  6.1. Drug discovery and design  6.2. Enzyme kinetics and inhibition  6.3. Chemical biology approach  6.4. Protein-ligand interactions  6.5. Bioorthogonal chemistry
  7. Materials chemistry  7.1. Polymer chemistry  7.1.1. Polymerization mechanism  7.1.2. Functional Polymers  7.1.3. Biodegradable Polymer  7.1.4. Conducting and semiconducting polymers  7.2. Nano Chemistry  7.2.1. Nanoparticles and nanostructures  7.2.2. Carbon-based nanomaterials  7.2.3. Quantum dots  7.3. Energy and Environmental Chemistry  7.3.1. Battery and Fuel Cell Chemistry  7.3.2. Green chemistry and sustainable materials  7.3.3. Photocatalysis

PHD → Organic chemistry → Natural products chemistry ↓


Alkaloids and terpenoids


Introduction

In the fascinating world of natural product chemistry, two major classes of compounds stand out because of their biological activity and structural complexity: alkaloids and terpenoids. Alkaloids are a diverse group of nitrogen-containing compounds found primarily in plants. They are known for their profound pharmacological effects, which have made them important in the development of medicinal drugs. On the other hand, terpenoids, also known as isoprenoids, are derived from five-carbon isoprene units and are one of the largest classes of natural compounds. Terpenoids play important roles in the biochemistry of all living organisms, acting as precursors to hormones and contributing to the aromatic and flavorful properties of plants.

Alkaloids

Alkaloids are naturally occurring chemical compounds that contain mostly basic nitrogen atoms. This category is particularly known for its powerful effects on the human body and, as a result, is widely used in medicine. They are commonly produced by a wide variety of organisms, including bacteria, fungi, plants, and animals. Alkaloids have a significant range of biological and pharmacological activities, ranging from toxic effects to therapeutic properties.

Chemical structure of alkaloids

The structure of alkaloids generally consists of a heterocyclic ring with nitrogen. This feature distinguishes them from other plant components. Alkaloids can be classified based on the type of nitrogen-containing ring system present in their molecules. Some of the common types of alkaloids are as follows:

  • Pyrrolidines: These contain a five-membered ring containing one nitrogen atom, like nicotine.
  • Pyridine: Consists of a six-membered ring with one nitrogen atom, as in piperine.
  • Tropanes: Known for their distinctive dicyclic structure, as seen in cocaine.
  • Indoles: It has a dicyclic structure in which a benzene ring is fused to a pyrrole ring, seen in compounds such as strychnine.

Examples of alkaloids

Let us understand some representative examples of alkaloids through structural formulas:

Nicotine

Nicotine is found in tobacco plants and has stimulant properties.

nicotine composition

Caffeine

Caffeine, commonly found in coffee and tea, is a stimulant to the central nervous system.

Caffeine Composition

Medicinal importance of alkaloids

Alkaloids are important in pharmaceuticals because of their wide range of activities. They can act as stimulants, inhibitors, or sedatives, providing essential medicinal properties. Examples of their use include:

  • Analgesics: Such as morphine and codeine, derived from opium.
  • Antimalarial: Quinine extracted from cinchona bark.
  • Anticancer: Vinblastine and vincristine are derived from periwinkle plants.

Terpenoids

Terpenoids, also known as isoprenoids, are an important class of secondary metabolites. They are composed of five-carbon units known as isoprene units. Terpenoids are found in many species, including plants, animals, and microorganisms. Known for their aromatic properties, they are also integral to important biological processes.

Chemical structure of terpenoids

The structure of terpenoids is based on the combination of isoprene units. The basic unit structure can be represented as:

C5H8
C5H8

Types of terpenoids: Depending on the number of isoprene units, terpenoids can be classified into several categories:

  • Monoterpenes: composed of 2 isoprene units (C 10 H 16 ), found in essential oils such as limonene and menthol.
  • Sesquiterpenes: composed of 3 isoprene units (C 15 H 24 ), such as farnesene.
  • Diterpenes: Contain 4 isoprene units (C 20 H 32 ), e.g. retinol (vitamin A).
  • Triterpenes: Contains 6 isoprene units (C 30 H 48 ), for example, squalene.
  • Tetraterpenes: composed of 8 isoprene units (C 40 H 64 ), including carotenoids.

Examples of terpenoids

Let us look at some important terpenoids illustrated through structural examples:

Limonene

Limonene is a common monoterpene responsible for the aroma of citrus fruits.

Limonene Structure

Squalene

Squalene, a triterpene, is a precursor to steroids and is found in olive oil.

squalene structure

Biological roles of terpenoids

Terpenoids have many roles in different organisms, including:

  • Defense mechanism: Many plants use terpenoids to repel herbivores.
  • Hormonal precursors: Terpenoids such as gibberellins are plant hormones.
  • Pigments and antioxidants: Carotenoids provide color and protect against oxidative damage.

Conclusion

Alkaloids and terpenoids provide fascinating insight into the diversity and complexity of natural product chemistry. Alkaloids are important for their wide range of medical applications, while terpenoids are important for their structural roles and biological functions. Their discovery continues to inspire chemical research, leading to the development of new and better medicines as well as aiding our understanding of plant biology and ecology.


PHD → 2.4.1


U
username
0%
completed in PHD

← Prev (2.4)
Natural products chemistry
Next (2.4.2) →
Steroids and Flavonoids

Comments 



Alkaloids and terpenoids

https://www.chemistryelite.com/phd/2.4.1?ceal=en