Lab 1 Flashcards
define drugs
synthetic or biological compounds used in the treatment or prevention of disease
How do most drugs produce physiological changes?
by binding to biological receptors
the knowledge of ________ is used to predict the physiochemical properties and potential biological effects of drugs
MOLECULAR STRUCTURE
name some physiochemical properties that are the basis for pharmacological and pharmaceutical evaluation
crystalline structure
solubility
melting/boiling point
polarity
lipophilicity
pka
steric effects
partition coefficient
give 2 words to describe the word “pharmacological”
pharmacodynamic and pharmacokinetic
pharmacodynamics studies what?
the effects of drugs ON THE BODY (mechanism of action, therapeutic and adverse effects”
pharmacokinetics studies what?
the effect of the BODY on the drug (ADME)
PHYSIOCHEMICAL, PHARMACODYNAMIC, AND PHARMACOKINETIC EFFECTS ARE INFLUENCED BY ____________
drug concentration
define “molecular constitution”
describes the IDENTITY and CONNECTIVITY of the atoms in a molecular entity
does “molecular constitution” take into account double and triple bonds? what about spatial arrangement?
takes into account single/double/triple bonds but NOT spatial arrangement
what is a “molecular entity”
any chemically or isotopically distinct atom/molecule/ion/pair/radical ion, etc which can be distinguished as a SEPARATELY DISTINGUISHABLE ENTITY
true or false
REGARDLESS of the administration route, drugs MUST be in solution in order to be permeable and thus absorbed
true
when comparing molecules of similar polarity, ____(large or small) molecules are generally less soluble in water than the alternative
LARGE molecules are LESS soluble in water
true or false
drug permeability is not limited by molecular size
false
compounds with molecule size greater than 100nm and molecular weight greater than 1000g/mol do NOT DIFFUSE READILY through the cell membrane, and transport mechanisms may be inept for this size
what imparts specific properties to a drug?
its functional group
define polarity
the difference in electronegativity within a molecular bond
true or false
polarity plays a key role in molecular interactions
true
molecules containing ___ and ___ are polar
ionic compounds such as ___, ____, and ____ are polar and are electrolytes
_____ and ____ are nonpolar (hydrophobic/lipophilic)
- oxygen and nitrogen
- salts, acids, and bases
- unsubstituted aromatic rings and aliphatic chains
functional groups can modify ______ properties such as……
physiochemical properties such as taste, solubility, and stability
what is the SOLUBLE SALT of acyclovir
acyclovir phosphate
what is the INSOLUBLE salt of chloramphenicol?
what is it formulated as?
chloramphenicol palmitate
formulated as a tasteless suspension
____, _____, and _____ are ____ groups and are very susceptible to hydrolysis
amides, esters, and lactams are NEUTRAL groups and are very sensitive to hydrolysis
can the proximity (distance) of each functional group to each other alter the properties of each group, and the overall properties of the drug?
yes
define chirality
the geometric property of a rigid object of being NON-SUPERPOSABLE on its mirror image
achiral definition
an object that IS superposable on its mirror image
define chirality centre
an atom holding a set of ligands in a spatial arrangement that is non-superposable on its mirror image
define an isomer
one of several chemical species (or molecular entities) that have the SAME stoichiometric molecular formula, but different constitutional/stereochemical formulae and HENCE DIFFERENT PHYSICAL AND/OR CHEMICAL PROPERTIES
do isomers have the same physical and chemical properties?
no – not necessarily.
isomers have the same stoichiometric formulae BUT different constitutional or stereochemical formulae
further classify isomers
2 types of isomers: constitutional or stereoisomers
differentiate between constitutional isomers and stereoisomers
constitutional isomers have the same molecular formula, but different connectivity (sequence of the atoms) and they differ in their physicochemical properties
stereoisomers have the same chemical formula and same order of attachment, but the groups differ in their spatial arrangement (3D)
stereoisomers can be divided into conformational and configurational
differentiate between configurational and conformational isomers
both are stereoisomers (same molecular formula, same order of connectivity, but different spatial arrangement)
With conformational isomers, they can be interconverted by rotations about single bonds
configurational isomers CANNOT be interconverted by rotations about single bonds, either due to restricted rotation (ie: cis-trans) or not (optical: enantiomers and diastereomers).
configurational isomers MAY SHARE SOME PHYSICOCHEMICAL PROPERTIES BUT DIFFER IN SPECIFICITY TO RECEPTOR BINDING AND ENZYME SUBSTRATE
2 molecules have the same molecular formula, same connectivity, cannot be interconverted about single bonds (due to restricted rotation)
classify these 2 molecules
cis-trans isomers (geometric)
2 molecules have the same molecular formula, same connectivity, and can be interconverted by rotation about single bonds
classify these 2 structures
conformational isomers
2 molecules have the same molecular formula, but the atoms are NOT connected in the same order (not the same connectivity)
classify these 2 structures
constitutional isomers — either functional, positional, or skeletal
2 molecules have the same molecular formula, same connectivity, CANNOT be interconverted by rotation about single bonds (NOT due to restricted rotation)
classify these 2 molecules
optical isomers – either enantiomers (non-superimposable mirror images) or diastereomers (non-superimposable non mirror images)
define cis- trans- isomers
2 molecules that have the same molecular formula, same order of atoms (connectivity) but CANNOT be interconverted due to restricted rotation about a carbon bond (either double bond or in a ring)
a sample is said to possess optical activity if….
the sample of material is able to rotate the plane of polarization of a beam of transmitted plane-polarized light
optical rotation is the classic distinguishing characteristic of systems containing unequal amounts of ______(what kind of moelcules)
ENANTIOMERS
true or false
enantiomers are stereoisomers
true
an enantiomer causing rotation in a clockwise direction (when viewed in the direction facing ____) is said to be ______ and its chemical name or formula is designated with what prefix?
FACING THE ONCOMING LIGHT BEAM, dextrorotatory, (+) prefix
an enantiomer causing rotation in a counter clockwise direction is ____ and has ___ prefix
laevorotory, (-)
what are optical isomers?
how are they able to rotate plane-polarized light?
same molecular formula, same connectivity (stereoisomers) that are not able to be interconverted (NOT due to restricted rotation).
basically they are either enantiomers or diastereomers
they are able to rotate plane polarized light due to their CHIRAL CENTERS
what is a chiral center
an asymmetric atom (generally carbon) with 4 different chemical groups
how can you calculate the maximum number of stereoisomers possible of optical isomers?
2^n, where n is the number of CHIRAL CARBONS present in the molecule
true or false
enantiomers are NOT IDENTICAL in their physical properties
FALSE – they are identical in all physical properties EXCEPT that they rotate the plane of polarized light in an equal, but opposite direction
enantiomers have the SAME CHEMICAL PROPERTIES except when…..
another chiral molecule is involved
the degree of rotation of enantiomers is dependent on what?
the concentration of the solution
what is a racemic mixture?
an equimolar mixture of a pair of enantiomers.
do racemic mixtures exhibit optical activity?
NO
How is the chemical name or formula of a racemic mixture distinguished from those of the enantiomers it contains?
by the prefix (k) or rac- or racem-
OR the symbols R and S
to be diastereoisomers, at least one chiral carbon must ____ and at least one chiral carbon must be _____
at least one must be the same (R,R) and at least one must be different (R,S)
what can you say about the physical and chemical properties of enantiomers and diastereomers
enantiomers have the SAME physical properties, except for the fact that they rotate the plane of polarized light in an equal but opposite direction. They have the same chemical properties EXCEPT when another chiral molecule is involved
diastereomers have DIFFERENT PHYSICAL PROPERTIES and have some differences in chemical behavior towards both achiral and chiral reagants
what are epimers?
stereoisomers (same molecular formula, same connectivity) that contain more than one chiral carbon and differ in configuration at JUST ONE STEREOCENTER
what are meso compounds?
stereoisomers with the internal plane of molecular symmetry
EACH HALF of a meso compound is….
a non superimposable mirror image
true or false
meso compounds are optically inactive
TRUE
the individual chiral centers in a meso compound are optically active and rotate the plane of polarized light in equal and opposite directions.
HOWEVER, this cancels the optical activity of the molecule as a whole, and thus meso compounds are optically INACTIVE
the Fischer-Rosanoff convention is no longer used.
D is equivalent to the current ___ while L is equivalent to the current ___
D —> R
L –> S
____ provides the sequence rules used to assign R and S configuration to stereocenters
the Cahn-Ingold Prelog System
give the steps of assigning R and S configurations, according to the Cahn-Ingold Prelog System
- Identify chiral carbon
- Assign a priority to each chiral atom based on the molecular (atomic) number. The higher the molecular number, the higher the priority
- in case of a tie, use the next atoms along the chain
- if clockwise, R. if counterclockwise, S
- The lowest priority group should always be directed AWAY FROM YOU. if it is directed towards, the assigned configuration reverses
give the formula for retention factor
Rf = distance moved by compound/distance moved by solvent front
