Organic Chemistry Flashcards
Gas-Liquid Chromatography
A laboratory technique used to separate small quantities of molecules by their boiling points.
Gas-liquid chromatography can be used to determine the purity of a sample.
Electrophile
An electron-poor molecule that can accept a pair of electrons.
Electrophile is synonymous with Lewis acid.
Carbanion
A molecule containing a carbon atom with a negative charge
Carbanions are nucleophilic and have a tetrahedral geometry.
Diastereomers
Stereoisomers that are non-superimposable non-mirror images.
Diastereomers have different chemical and physical properties.
Monosaccharide
The simplest of carbohydrates and the building blocks of more complex sugars
Monosaccharides are also called single sugars and include glucose, fructose, ribose, and deoxyribose.
Nucleophile
An electron-rich molecule that can donate a pair of electrons.
Nucleophile is synonymous with Lewis base.
Absolute Configuration
The spatial arrangement of atoms around a chiral center.
The absolute configuration can be R or S.
Anomeric Carbon
The anomeric carbon is the carbon that forms the new stereocenter during cyclization of a linear carbohydrate.
The anomeric carbon is also the carbonyl carbon in the linear form of the carbohydrate.
Specific Rotation
A measure of how much a chiral compound rotates plane-polarized light.
Compounds that rotate plane-polarized light clockwise and counterclockwise are called dextrorotatory and levorotatory, respectively.
Anomer
Cyclic carbohydrates that differ in absolute configuration only at the anomeric carbon but are otherwise identical.
Anomers are also epimers.
Carbocation
A molecule containing a carbon atom with a positive charge
Carbocations are electrophilic and have a trigonal planar geometry.
Column Chromatography
A laboratory technique used to separate large quantities of molecules by polarity.
In column chromatography, the less polar compounds elute first and the more polar compounds elute later.
Structural Isomers
Isomers that differ in the way their atoms are bonded together.
Structural isomers are also called constitutional isomers.
Stereoisomers
Isomers that differ in the spatial orientation of their atoms but have the same chemical bonds.
Stereoisomers include conformational isomers, diastereomers, and enantiomers.
Glycosidic Linkage
A covalent bond that links two carbohydrate molecules.
The glycosydic linkage is named based on the absolute configuration of the anomeric carbon and the numbers of the carbon atoms involved in the linkage.
Steric Hindrance
The inhibition of a chemical reaction due to the congestion of large substituents on the reactant molecules.
The larger the substituents, the more impact steric hindrance has on the rate of the reaction.
Epimer
Diastreomers with chiral centers that differ in absolute configuration at only a single chiral center.
Glucose and galactose are epimers with the same absolute configuration at every chiral center except at the C-4 carbon.
Distillation
A laboratory technique used to separate large quantities of molecules by their boiling points.
In distillation, the compound to be isolated is boiled off and collected, leaving the impurities that have higher boiling points behind. Sometimes, it is the impurity that is boiled off, leaving the compound of interest behind.
Chiral Center
An atom bound to four different substituents.
Chiral centers are also called stereocenters and stereogenic centers.
Conformational Isomers
Stereoisomers that differ in rotation about a single bond.
Conformational isomers are also called rotamers and conformers.
High Performance Liquid Chromatography
A laboratory technique that uses high pressures to achieve higher quality separation of mixtures.
HPLC generally refers to a more advanced version of column chromatography but can also be applied to other forms of chromatography to enhance separation.
Enantiomers
Stereoisomers that are non-superimposable mirror images of each other
Enantiomers rotate plane-polarized light by equal amounts but in opposite directions. Asides from optical activity, enantiomers have identical chemical and physical properties.
Isomer
Compounds with the same chemical formula.
Despite containing the same atoms, isomers can have different chemical and physical properties.
Thin-Layer Chromatography
A laboratory technique used to separate small quantities of molecules by polarity.
Thin-layer chromatography can be used to determine whether or not a reaction has gone to completion.
