10/10 Flashcards
what is a stereoisomer?
a compound with the same chemical formula, but a different 3-dimensional arrangement of atoms. ( how they look in space)
Why do we care about stereoisomers?
because they can have different effects in the body
Thalidomide was a drug prescribed for morning sickness. After some research, they found that it was a mixture of _____
stereoisomers
Drug companies have to prove to the FDA that a drug being proposed has either: (regarding stereoisomers)
single chemical entity, (one version of the stereoisomer) or
prove that both of the stereoisomers in the racemic mixture is safe
what makes up a stereoisomer?
stereocenter/chiral center/stereogenic center
and either a enantiomer or diastereomer
where a wedge or dash exists for this class, that is the
stereocenter
What are the 2 types of stereoisomers
Enantiomers and diastereomers
how do you know when you are dealing with a diastereomers?
all of their properties are different. They don’t have a lot incommon except their chemical formula and arrangement of atoms.
what is the one property that is different in an enantiomer?
enantiomers are mirror images except for their optical rotation
what is the optical rotation?
something that rotates polarized light
left (counterclockwise) is the negative direction
right (clockwise) is the positive direction
in a stereocenter: for carbon atoms that only contain single bonds, there must be ______ different groups attached
4
how to denote a stereocenter without a wedge or dash?
an asterisck
which direction are solid wedges?
which direction are dashes?
in plane groups in: FRONT coming towards you
out of plane groups: BACK going away from you
what are the rules to labeling stereocenters of a tetrahedral?
- prioritize the atoms by increasing atomic number (look at the periodic table)
*if 2 or more are the same, look at what they are attached to to find a point of difference. - Only consider atoms 1-3
* if it is clockwise (to the right)=R stereoisomer
* if is it counterclockwise (to the left= S stereoisomer - look at group 4.
*if it is on the dash, the stereocenter is on the dash, keep it as it is
*if it is on the wedge, invert the isomer.
hydrogen always has the least ____ when labeling stereocenters
priority. The atomic number is 1, nothing is smaller than 1
for carbons in an alkene, there must be two different groups attached to
each carbon of the double bond
steps to labeling an alkene stereoisomer:
- find the stereocenter. this is where you have a double bond with 2 carbons.
- Look at the right side and decide the priority
- look at the left and decide the priority
- draw a line through the double bond. If the priorities are both on the top or both on the bottom it is a Z isomer.
If the priorities are on the opposite side then it is an E isomer.
when labeling stereoisomers on alkenes, what are the naming options?
E=opposite side
Z=same side
every double bond has a ____ carbon and a _____ carbon
left
right
enantiomers can have 1 or more
stereocenters
how to tell if you have an enantiomers in a picture of 2 structures?
all the stereocenters must be switched between 2 structures
why can enantiomers impact how a compound interacts within the body?
the body recognizes the different stereocenter.
(i.e. spearmint vs. caraway seed smells)
in a diastereomers you have to have a minimum of ____ stereocenters
2
how to tell if you have an diastereomers in a picture of 2 structures?
one stereocenter changes and one stays the same (dash vs wedge)
diastereomers structures are completely _______
different. Can even happen in different physical properties and have a liquid and a solid
Enantiomer isomers usually involves one form that can be dangerous, usually diastereomers extra form doesn’t really do
much of anything
what is the standard aromatic compound?
Benzene
heterocycles
a ring compound that contains a heteroatom
The benzene ring is very _______
stable and common