Diastereomeric recrystallization is a technique used in organic chemistry to separate diastereomers, which are types of stereoisomers. Unlike enantiomers, which are non-superimposable mirror images of each other and have identical physical properties except for their interactions with plane-polarized light, diastereomers have different physical properties due to their non-mirror-image relationships.
Dynamic kinetic resolution (DKR) is a strategy in asymmetric synthesis that combines enantioselective transformations with racemization processes. The goal is to selectively convert a racemic mixture of substrates into a single enantiomer, thereby increasing the yield of the desired chiral product. In a typical scenario of DKR, a racemic substrate is subjected to a catalytic reaction that preferentially transforms one enantiomer more than the other.
Dynamic stereochemistry refers to the study of stereochemical aspects of molecules that are in constant motion or undergoing rapid conformational changes. Unlike traditional stereochemistry, which often focuses on static conformations and fixed spatial arrangements of atoms in molecules, dynamic stereochemistry examines how these arrangements can change over time due to factors like heat, solvent interactions, or reactions.
Eclipsed conformation refers to a specific arrangement of atoms or groups in a molecule, particularly in the context of rotational conformations around a single bond. In an eclipsed conformation, the groups or atoms attached to the carbon atoms involved in the bond are positioned directly in front of each other when viewed along the axis of that bond. This contrasts with the staggered conformation, where the atoms or groups are positioned such that they alternate and minimize steric interactions.
Enantiomers are a type of stereoisomer that are non-superimposable mirror images of each other. These molecules have the same molecular formula and connectivity of atoms but differ in their three-dimensional arrangement. Enantiomers typically occur in chiral molecules, which possess a carbon atom bonded to four different substituents, leading to two distinct spatial configurations.
Enantiomer self-disproportionation is a phenomenon observed in asymmetric reactions where a racemic mixture (a 1:1 mixture of two enantiomers) separates into two fractions that have differing concentrations of the enantiomers. In simpler terms, it describes a process in which two enantiomers in a mixture can separate such that one of the enantiomers is more prevalent in one portion of the mixture than in the other.
Enantiomeric excess (ee) is a measure of the purity of a chiral compound in terms of the proportion of one enantiomer relative to the other. Enantiomers are pairs of molecules that are non-superimposable mirror images of each other, and they often differ in their biological activity and properties.
An enantiopure drug refers to a pharmaceutical compound that consists almost entirely of one enantiomer, which is one of two non-superimposable mirror-image forms of a chiral molecule. In many cases, drugs are chiral and can exist as two enantiomers: one may be therapeutically active while the other may be less active, inactive, or even harmful.
Enantioselective synthesis refers to a process in chemistry where a chemical reaction produces one enantiomer (a specific chiral form) over another in a preferential manner. Enantiomers are molecules that are non-superimposable mirror images of each other, similar to how left and right hands are related.
Endo-exo isomerism is a type of stereoisomerism that occurs in certain bicyclic compounds, particularly those containing bridgehead atoms. The terms "endo" and "exo" refer to the spatial arrangement of substituents relative to the plane of the bicyclic structure. In this context: - **Endo isomer**: In the endo configuration, substituents (e.g.
An epimer is a type of stereoisomer that differs from another compound in the configuration around just one specific stereogenic center (chiral center). This means that while the two compounds have the same molecular formula and may be very similar overall, they have different spatial arrangements of atoms at only one of their chiral centers. Epimers are particularly common in carbohydrate chemistry. For example, glucose and galactose are epimers because they differ at only one carbon atom (C4).
The term "Eudysmic ratio" is not widely recognized in mainstream scientific literature, and it may not refer to a well-defined concept in fields such as biology, medicine, or related sciences. It could be a term used in a specific niche or by a particular research group.
E–Z notation is a system used in organic chemistry to describe the stereochemistry of alkenes, specifically the relative positions of substituents attached to the double bond. It is particularly useful when there are multiple substituents on both sides of the carbon-carbon double bond (C=C). The notation is based on the Cahn-Ingold-Prelog priority rules, which assign priorities to different substituents based on atomic number and other factors.
A Fischer projection is a two-dimensional representation of a three-dimensional organic molecule, specifically used for depicting the stereochemistry of carbohydrates and amino acids. It was developed by Emil Fischer in the early 20th century. In a Fischer projection, the molecule is represented as a vertical and horizontal arrangement of bonds. The vertical lines represent bonds that project away from the viewer (into the plane of the paper), while the horizontal lines represent bonds that project towards the viewer (out of the plane of the paper).
The term "fuzzy complex" can refer to different concepts depending on the context in which it is used. Here are a couple of interpretations: 1. **Fuzzy Logic and Fuzzy Complex Systems**: In the realm of systems theory and computer science, "fuzzy complex" may relate to complex systems that exhibit fuzzy characteristics. Fuzzy logic is a form of many-valued logic that deals with reasoning that is approximate rather than fixed and exact.
The Fürst-Plattner Rule is a guideline used in mineral processing, particularly in the context of determining the viability of extracting metals from ore. It specifically relates to the extraction of silver from silver-bearing ores, although its principles can sometimes be applied to other metals as well. The rule suggests that the value of the metal that can be extracted must exceed the cost of recovering it, including expenses related to mining, milling, and refining the ore.
The Gauche effect refers to a conformational preference observed in certain organic molecules, particularly in butane and other alkanes. In these molecules, the Gauche conformation is one where two substituents (or hydrogen atoms) are positioned approximately 60 degrees apart, which can lead to steric interactions and influences on the overall stability of the molecule.
A Haworth projection is a method for representing the cyclic structures of sugars (carbohydrates) in a two-dimensional form while keeping their three-dimensional stereochemistry in mind.
Hexol is a brand name for a type of solvent that is primarily composed of a mixture of hydrocarbons. It is used in various industrial applications, including cleaning, degreasing, and as a paint thinner. Hexol is capable of dissolving greases, oils, and other substances, making it useful in maintenance and manufacturing processes. In particular, it may refer to specific formulations that are designed for particular uses, such as in automotive or industrial settings.
Homochirality refers to the phenomenon where biological molecules, such as amino acids and sugars, exhibit a preferential uniformity in their chirality, meaning they exist in one specific enantiomeric form rather than a mixture of both. In molecular chemistry, chirality describes the property of a molecule that is not superimposable on its mirror image, much like left and right hands.