isomers

Question 1

what’s a functional group?and what does it do?

Answer 1

Portion of a molecule that is a
recognizable group of bound atoms
Give the molecule its properties
responsible for all biological interactions

Question 2

pros and cons of functional group in drugs?

Answer 2

PROS
Stable in water/physiological conditions
Unlikely to react with biological molecules
CONS- However all groups may be further functionalised by enzymes AND result in toxic compounds being generated
Very difficult to predict

Question 3

what is an isomer?

Answer 3

Molecules with the same molecular formula
(the same number of atoms of each element),
but different structural or spatial
arrangements of the atoms within the
molecule

Question 4

what are the different types of isomers?

Answer 4

Constitutional
Stereoisomer(Enantiomers
Diastereomers)

Question 5

what are constitutional isomers?

Answer 5

are different compounds which share the same molecular formula but have different bonding sequence.(structural isomer)

Question 6

what can conformers do that structural isomers can’t do?

Answer 6

Unlike structural isomers, conformers are usually
continually interconverting

Question 7

how do we visualise conformers?

Answer 7

Newman projections

Question 8

Are humans chiral?

Answer 8

Yes, humans exhibit chirality due to molecules in our body, such as amino acids and sugars, existing as single enantiomers.

Question 8

What composes our proteins?

Answer 8

Our proteins are made up of amino acids, which naturally occur as single enantiomers.

Question 8

Is the human body chiral in structure?

Answer 8

Yes, the human body exhibits chirality as certain molecules, like amino acids, have a specific right-handed twist in their structure.

Question 8

Why is chirality significant in drug interactions?

Answer 8

Drugs designed for the body must interact with chiral molecules. The specific enantiomer can dictate the drug’s effect within the body.

Question 9

Do different enantiomers of drugs have varying effects?

Answer 9

Yes, sometimes different enantiomers of drugs can have different or even opposing effects within the body.

Question 10

What properties are identical between individual enantiomers and their mirror images?

Answer 10

melting point, analytical spectra (e.g., NMR, IR, UV), density, and aqueous solubility.

Question 11

In what way do enantiomers differ, indicating their optical activity?

Answer 11

Enantiomers differ in their ability to rotate the plane of polarized light (PPL) and are described as optically active (optical isomers).

Question 12

What are some examples of prescribed medicines exhibiting levorotation?

Answer 12

Levocetirizine (antihistamine), Levothyroxine (for treating hypothyroidism), and Levonorgestrel (progestogen; steroid hormone)

Question 13

What are examples of dextrorotatory drugs used for specific purposes?

Answer 13

Dextromethorphan: Used as a cough suppressant.
Dextropropoxyphene (often in combination with paracetamol): Available as an analgesic (pain reliever).

Question 14

What is the significance of Fischer Projections in representing carbohydrates?

Answer 14

Fischer Projections are commonly used to represent carbohydrates, the naturally occurring biological molecules, by positioning the most oxidized group at the top and the longest carbon chain vertically.

Question 15

What are Fischer Plane Projections used for?

Answer 15

Fischer Plane Projections are used to simplify the representation of molecules in three dimensions while retaining their stereochemical information

Question 16

Why can’t we supply thalidomide to pregnant women as a homochiral drug if only one enantiomer is responsible for teratogenic effects?

Answer 16

Thalidomide’s enantiomers interconvert under physiological conditions, making it unsafe for pregnant women even when used as a single enantiomer.

Question 17

What are enantiomers?

Answer 17

Enantiomers are stereoisomers that are non-superimposable mirror images of each other.

Question 18

Define diastereomers

Answer 18

Diastereomers are stereoisomers that are not non-superimposable mirror images.

Question 19

How many stereoisomers can a compound with n chiral centers have at most?

Answer 19

A compound with n chiral centers can have a maximum of 2n stereoisomers.

Question 20

What is a meso compound, and why is tartaric acid considered achiral despite having chiral centers?

Answer 20

A meso compound possesses an internal plane of symmetry. Tartaric acid is achiral despite having chiral centers because it contains an internal plane of symmetry, making it optically inactive

Question 21

What is internal compensation in meso compounds?

Answer 21

Internal compensation in meso compounds refers to the cancellation of optical rotation from one side of the molecule by the other, resulting in optical inactivity.

Question 22

How can a meso compound be identified?

Answer 22

It must have at least two stereocenters.
A compound with only one chiral center cannot be a meso compound.
It must possess an internal mirror plane.
The meso compound must exhibit symmetry about the mirror plane.
Each opposing stereocenter must have different absolute configurations

Question 23

What are the five main types of organic reactions?

Answer 23

Addition reactions
Elimination reactions
Substitution reactions
Oxidation and reduction reactions
Rearrangement reactions

Question 24

What are the subdivisions of substitution reactions?

Answer 24

Electrophilic Substitution
Electrophilic Aromatic Substitution
Nucleophilic Substitution
Nucleophilic Aliphatic Substitution
Nucleophilic Acyl Substitution
Nucleophilic Aromatic Substitution

Question 25

What are the characteristics of a Nucleophile?

Answer 25

Electron Rich - nucleus loving
Possesses a pair of electrons (lone pair) in a high energy filled orbital
Might carry a negative charge (though often neutral)
Frequently includes heteroatoms like O, N, or S; can also be a carbon anion or hydride

Question 26

What defines an Electrophile?

Answer 26

Electron Poor - electron loving
Contains an empty atomic/molecular orbital or a low energy antibonding orbital
May bear a positive charge (though often neutral)
Commonly involves heteroatoms like O, N, or S; can also be a carbon cation or proton

Question 27

What effect does the greater electronegativity of halogen atoms have on the C-X bond in alkyl halides?

Answer 27

The greater electronegativity of halogen atoms results in a permanently polarized C-X bond, with the electron-deficient carbon (δ+) susceptible to attack by electron-rich species (nucleophiles).

Question 28

Why is the carbon atom in alkyl halides considered an electrophile?

Answer 28

The electron-deficient carbon in alkyl halides acts as an electrophile, making it susceptible to attack by nucleophiles, leading to substitution reactions by displacing the suitable “leaving group.”

Question 29

What is the recurring theme in many organic chemistry reactions involving alkyl halides?

Answer 29

In organic chemistry reactions involving alkyl halides, the recurring theme is the interaction between a nucleophile (electron-rich species) and an electrophile (electron-deficient species), leading to substitution reactions.

Question 30

What do reaction mechanisms illustrate?

Answer 30

Reaction mechanisms depict the movement of electrons using curly arrows, showcasing how electron pairs shift during a chemical reaction.

Question 31

What is the role of curly arrows in reaction mechanisms?

Answer 31

Curly arrows indicate the movement of electrons from a pair of electrons to an electron-deficient atom or group, showing the flow of electron density.

Question 32

How do reaction mechanisms benefit understanding?

Answer 32

They offer insight into the sequence of steps in a chemical reaction, detailing how bonds break and form, providing a deeper understanding of the reaction process.

Question 33

What type of compounds are usually involved in substitution reactions?

Answer 33

Saturated compounds containing only single bonds, such as bromomethane (CH3Br) and methanol (CH3OH).