Isomerism and Stereochemistry Flashcards Preview

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Flashcards in Isomerism and Stereochemistry Deck (35)
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1
Q

Stereochemistry: chemistry of molecules in 3D

A

Organic molecules
> structural isomers + stereoisomers
> conformational + configurational
> optical + geometrical

2
Q

Structural isomers

A

same molecular formula
atoms bonded in different orders
Different properties

3
Q

Conformational

A

rotation around σ bonds and 3D shape of sp3 centre

4
Q

Stereoisomers

A

same molecular formula
atoms bonded in same order
different 3D arrangement

5
Q

Configurational

A

No conversion by rotation of single bond

6
Q

Geometrical

A

cis/trans
E/Z

stereoisomers that arise due to restricted rotation
within a molecule

7
Q

Optical

A

D/L
S/R

8
Q

how many structural isomers?

A

7

9
Q

Montelukast:

A

Symptomatic relief of seasonal allergic rhinitis in patients with asthma and prophylaxis of asthma in children (note: oral formulation)

10
Q

conformational isomers (CI)

A

configurational isomers: optical isomers (OI)
configurational isomers: geometrical isomers (GI)

11
Q

tetrahedral angle, degree?

A

109.5 degree

12
Q

All single bonds are ____to rotate
Although might be restricted by nearby ______ groups

A

free
bulky

13
Q

cis

A

same side

14
Q

trans

A

opposite side

15
Q

highest priority?

A

biggest atomic number

16
Q

geometric can happen only when…

A

two different groups at each end of double bond

17
Q

use E/Z for when…

A

you have multiple functional groups and there are different priorities dependent on the Ar

18
Q

carbon has _____ priority than hygrogen

A

higher

19
Q

e.g. 1-bromo-1-chloro-2-methylbut-1-ene:
search diagram

A

Bromine is higher priority than chlorine
1. Carbon is same priority as carbon
2. Carbon is higher priority than hydrogen

For linear carbon chains, the longest one is always highest priority

20
Q

double bond - rotation?

A

cannot rotate

21
Q

when c attached to 4 diff groups;

A

When a carbon is attached to 4 different groups/ arms present, none of which are the same

22
Q

Configurational Isomers: chirality
think of left and right hand…

A

cannot be superimposed

23
Q

What is the Achiral carbon?

A

At least 2 same groups/atoms present
Yes plan of symmetry

compound and its mirror image are the same, can be superimposed

24
Q

Define Enantiomers:

A

Same physical/chemical properties
Differ in activities with plan polarised light that gives rise to optical isomerism, and also in their pharmacological actions

non-superimposable

25
Q

Chiral centre

A

the C in the middle functional groups attaches to it

26
Q

Chiral molecules ______ plane-polarised light: this is called ______ activity

A

rotate

optical

27
Q

Racemic Mixture

A

A mixture that contains more of one enantiomer than the other is optically active

28
Q

rotation - naming:
clockwise / anti-clockwise

A

Rotation clockwise direction: dextrorotatory, (+)
Anticlockwise rotation: levorotatory, (−)

29
Q

Examples of drugs that are racemic mixtures

A

atenolol
warfarin

30
Q

Configurational Isomers: D and L system are…

A

Fisher: (+)-glyceraldehyde enantiomer=D-glyceraldehyde,
(-)-glyceraldehyde enantiomer=L-glyceraldehyde

31
Q

How to assign R & S system?

A

1) Priority: from 1 to 4 = assigned on basis of atomic number.
Higher atomic number gets higher priority

2) Substituents: if no priority, the next set of atoms in the unassigned groups is examined

3) Double or triple bonds: assigned priorities as if both atoms were duplicated or triplicated

4) Arrange (rotate) the molecule: group 4 is pointing away from the viewer

32
Q

learn the different lines

A

thick black - pointing towards you
faint lines - pointing away from you

33
Q

Lowest-priority group always pointing ____ from us

A

away

34
Q

Each additional chiral centre generates ________ isomers

A

additional

35
Q

Labetalol

A

a member of the beta-blocker family (drugs that bind to beta-adrenergic receptors). It is used to treat hypertension, especially hypertension in pregnancy