A chiral auxiliary is a molecule or functional group that is introduced into a chemical reaction to temporarily impart chirality to a substrate that would otherwise be achiral. Chiral auxiliaries help guide the stereochemical outcome of reactions, leading to the selective formation of one stereoisomer over another. In practice, a chiral auxiliary is typically attached to a substrate to create a chiral environment around it, which influences how it reacts in synthetic transformations.
Chiral column chromatography is a specialized technique used in analytical and preparative chemistry to separate chiral compounds, which are molecules that exist in two non-superimposable mirror image forms known as enantiomers. Due to their distinct spatial arrangements, these enantiomers can exhibit different chemical behaviors and biological activities, making their separation crucial in various fields, including pharmaceuticals, food science, and environmental chemistry.
Chiral derivatizing agents (CDAs) are chemical compounds used in the analysis of chiral molecules, which are compounds that exist in two enantiomeric forms that are non-superimposable mirror images of each other. CDAs are employed primarily in chromatography and other analytical techniques to help differentiate between these enantiomers.
Chiral drugs are pharmaceutical compounds that possess chirality, meaning they exist in multiple forms that are mirror images of each other, known as enantiomers. This characteristic arises from the presence of a specific carbon atom (often referred to as a chiral center) that is bonded to four different substituents. Because of this asymmetry, two enantiomers can have significantly different biological activities, side effects, and pharmacokinetics.
Chiral inversion refers to the process of converting one enantiomer of a chiral molecule into its mirror-image counterpart. Chiral molecules are those that exist in two non-superimposable forms known as enantiomers, which are typically labeled as "R" and "S" forms based on their spatial configuration.
Chiral resolution, also known as enantiomeric resolution, is the process of separating a racemic mixture (a mixture that contains equal amounts of enantiomers) into its individual enantiomers. Enantiomers are molecules that are non-superimposable mirror images of each other, much like left and right hands.
A chiral switch refers to the process of developing a medication that is a specific enantiomer (one of two mirror-image forms) of a drug that has already been marketed as a racemic mixture, which contains both enantiomers. In pharmaceutical chemistry, chirality is significant because the two enantiomers of a chiral molecule can have different biological properties, including variations in efficacy, safety, metabolism, and side effects.
Chiral thin-layer chromatography (chiral TLC) is an analytical technique used to separate enantiomers or chiral compounds based on their optical activity. This method is particularly important in fields such as pharmaceuticals, where the enantiomeric forms of a compound can exhibit different biological activities or pharmacological effects. ### Key Features of Chiral TLC: 1. **Chirality**: Chiral compounds are molecules that exist in two non-superimposable mirror-image forms, known as enantiomers.
Chirality is a property of asymmetry important in several branches of science, particularly in chemistry, biology, and physics. An object or a molecule is considered chiral if it cannot be superimposed on its mirror image. This means that a chiral object has a distinct handedness, much like how left and right hands are mirror images of each other but cannot be aligned perfectly. In chemistry, chirality is most often discussed in the context of molecules.
Chirality-induced spin selectivity (CISS) is a physical phenomenon where chiral molecules exhibit a preference for spinning electrons in a certain direction. This effect is observed in systems that include chiral organic molecules, which are structures that cannot be superimposed on their mirror images, much like left and right hands. The key points about CISS are: 1. **Chirality**: Chiral molecules have non-superimposable mirror images.
Chirality in chemistry refers to the geometric property of certain molecules that makes them non-superimposable on their mirror images, much like how left and right hands are mirror images of each other but cannot be perfectly aligned on top of one another. This phenomenon arises because of the presence of an asymmetric carbon atom, typically a carbon atom bonded to four different substituents.
The term "chirality" refers to the property of an object being non-superimposable on its mirror image, similar to how left and right hands are mirror images of each other but cannot be perfectly aligned. Chirality plays a significant role in various scientific disciplines, especially in chemistry, biology, and materials science.
Cis–trans isomerism, also known as geometric isomerism, is a type of stereoisomerism where the spatial arrangement of groups or atoms in a molecule differs due to the restricted rotation around a double bond or within a ring structure. Here’s a breakdown of the concept: 1. **Cis Isomer**: In a cis isomer, similar or identical groups are positioned on the same side of a double bond or a ring structure.
Conformational isomerism, also known as conformers or conformational isomers, refers to the different spatial arrangements of a molecule that can be achieved by rotation around single bonds. Unlike structural isomers, which differ in the connectivity of atoms, conformational isomers differ only in their three-dimensional shapes due to the rotation around single sigma (σ) bonds.
A Cross-linked Enzyme Aggregate (CLEA) is a type of biocatalyst that involves the aggregation of enzymes and their subsequent cross-linking to enhance stability and activity in various applications. This process generally involves the following steps: 1. **Aggregation**: Enzymes are aggregated through methods such as adding salts, changes in pH, or heating. This aggregation can promote interactions between enzyme molecules that stabilize them when they are later cross-linked.
Cryptochirality refers to a phenomenon in which a chiral molecule exhibits a particular symmetry that makes it difficult to distinguish between its enantiomers (mirror-image forms) in certain contexts. Chirality is a property of asymmetry where a molecule cannot be superimposed on its mirror image. Typically, chiral molecules exist in two forms that are non-superimposable mirror images of each other, often designated as "left-handed" (S) and "right-handed" (R) configurations.
Cryptoregiochemistry is a term used in the field of organic chemistry that refers to the study of the stereochemical and regioselective outcomes of reactions involving molecules with multiple functional groups or centers that can interact in different ways. The prefix "crypto-" suggests hidden or obscure features, indicating that certain stereochemical or regioselective aspects may not be immediately apparent.
Cyclohexane is a six-membered carbon ring that can adopt various conformations due to the flexibility of its carbon-carbon single bonds. The most significant conformations of cyclohexane are the **chair**, **boat**, and **twist-boat** forms. Here’s a brief overview of these conformations: 1. **Chair Conformation**: - This is the most stable and preferred conformation of cyclohexane.
Desymmetrization is a concept used in various fields, particularly in chemistry and mathematics, referring to the process of breaking symmetry in a system that possesses symmetrical properties. In chemistry, desymmetrization is often discussed in the context of synthetic organic chemistry and is related to the design and synthesis of chiral molecules. Chiral molecules are those that cannot be superimposed on their mirror images, and they often have important implications in pharmaceuticals and biological activity.
Diastereomers are a type of stereoisomer that are not mirror images of each other. They occur when a molecule has multiple stereocenters (chiral centers) and varies at one or more, but not all, of those centers. This leads to different spatial arrangements of the atoms in the molecule, resulting in distinct compounds with different physical and chemical properties. For example, consider a molecule with two chiral centers.