11842725
Description
Flashcards by J yadonknow, updated more than 1 year ago
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Created by J yadonknow
over 6 years ago
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| Question | Answer |
| What are stereoisomers? | Isomers who's atoms are connected in the same order but have a different arrangement in space |
| What is a chiral/achiral stucture? | Superimposable/not superimposable at least 1 carbon, bonded to 4 different groups |
| What is the name of a chiral carbon atom? | Asymmetric carbon/stereocentre |
| What is a racemate? | A racemic mixture where the entantiomers are in 1:1 ratio |
| How can you tell if a reaction will produce a racemic mixture? | If the achiral reactants for a chiral product |
| Why is this important medically? | Many drugs are chiral, with only one enatiomer having the desired effect The opposite enatiomer may be biologically inactive or active, and produce undesired effects i.e. thalidomide |
| How do chiral molecules generally exist in nature? | Usually only 1 enatiomer, all amino acids are chiral EXCEPT Glycine ENATIOMERICALLY PURE |
| How do you describe which enatiomer you're talking about? | R/S system +/-(d/l) system based on polarisation of light D/L based on chemical degradation product |
| How do you use the R/S system? | 1. Identify the stereogenic centre 2.Assign priority to each group based on AN of first atom of group 3. If 2 AN are the same, go to next atom 4. Arrange so lowest priority group is pointing away (pointing into plane of paper behind) 5. Use 1-2-3 to determine if it's clockwise (R) or anticlockwise (S) So now you can name it (S)-alanine |
| What do the various lines denote in terms of 3D orientation? | Dashed line - into the plane of the paper wedge- bond out towards you solid- bond in plane of paper |
| How can you skip the bullshit stuff to tell if it's R or S? | If the hydrogen is coming out at us in space, then we ignore it and count 1-2-3, and put the opposite of this rotation, so if 1-2-3 clockwise then it's S not R |
| What are the properties of enatiomers? | Same physical properties except plane of polarisation rotation by S/R enantiomers Same chemical properties unless another chiral molecule is involved |
| What is (Anti)clockwise rotation of light polarity? What is important to keep in mind? | clockwise=+ or d anticlockwise=- or l Just because an enantiomers is clockwise, DOESN'T mean it rotates light clockwise |
| What are Diastereoisomers? | Stereoisomers that are NOT optically superimposable with one or more chiral centres can form multiple structures due to free rotation, which are isomeric |
| How do you derive the number of stereoisomers? | 2^n |
| Draw a diagram showing relationship between enantiomers and diastereomers | RS-SR Enant RR-SS Enant RS-SS Dia SR-RR Dia RS-RR Dia SR-SS Dia E- cute fit D-awkward grasp |
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