Elm 7 Drug Structures Flashcards
(31 cards)
Q: What are stereoisomers?
A: Molecules that have the same sequence of atoms but differ in the 3D arrangement of bonds at one or more atoms.
Q: What is a stereogenic center?
A: An atom that gives rise to stereoisomerism.
Q: Define conformational isomerism.
A: A type of isomerism where stereoisomers can be interconverted solely by the rotation of bonds.
Q: What is configurational isomerism?
A: Isomerism where stereoisomers cannot be interconverted by rotation of bonds, including optical isomerism and cis/trans isomerism.
Q: Define enantiomers.
A: Also known as optical isomers, they are pairs of compounds that are mirror images of each other and rotate polarized light in opposite directions.
Q: What is cis/trans isomerism?
A: Stereoisomerism where isomers differ in how groups are oriented either side of a double bond.
Q: What does chiral mean?
A: Describes a molecule that cannot be superimposed on its mirror image.
Q: What is a chiral center?
A: An atom, usually a carbon, that has four different groups attached to it, giving rise to chirality.
Q: What is the Cahn-Ingold-Prelog (CIP) system?
A: A method for classifying the configuration of atoms at a chiral center, designating enantiomers as R or S.
Q: What does the D/L system classify?
A: Stereoisomers of molecules based on their relationship to glyceraldehyde, mainly applicable to sugars and amino acids.
Q: How does the +/- system classify enantiomers?
A: Based on the direction an optical isomer rotates polarized light: (+) clockwise and (-) counterclockwise.
Q: Define diastereomers.
A: Stereoisomers that contain chiral centers but are not mirror images of each other.
Q: What are optical isomers (enantiomers)?
A: Compounds that are non-superimposable mirror images of each other and rotate polarized light in opposite directions.
Q: What does achirality mean?
A: Refers to molecules that do not have a chiral center, such as glycine.
Q: What are conformational isomers?
A: Molecules that exist in different forms due to the rotation of bonds.
Q: What are cis-trans isomers also known as?
A: Geometric isomers or E/Z isomers.
Q: What is the significance of enantiomers in drug binding?
A: Optically active drugs will have one enantiomer that binds to the target tighter due to better fit with the receptor’s binding sites.
Q: What is the concept of three-point binding?
A: It refers to the need for three points on a receptor to be blocked by three substituents of a molecule for maximum binding affinity. One isomer fits well, while the other does not.
Q: What are the three systems for classifying enantiomeric pairs?
A: The +/-, D/L, and R/S (Cahn-Ingold-Prelog) systems.
Q: How does the +/- system classify enantiomers?
A: Based on optical activity: (+) enantiomers rotate polarized light clockwise and (-) enantiomers rotate it counterclockwise.
Q: What is the D/L system based on?
A: The relationship to glyceraldehyde, with D-enantiomers related to (+)-glyceraldehyde and L-enantiomers related to (-)-glyceraldehyde.
Q: Why is the D/L system mainly used for sugars and amino acids?
A: It relies on an obvious structural relationship to glyceraldehyde, which is most applicable to these groups.
Q: How does the Cahn-Ingold-Prelog (CIP) system classify enantiomers?
A: Enantiomers are classified as R (rectus) or S (sinister) based on the priority of substituents around a chiral center.
Q: What is a chiral center?
A: An atom, usually carbon, with four different groups attached to it, leading to chirality.
