BMP: Drug Desgin 4

Question 1

What is the electron congifuration of O2 if its atomic no. is 8

Answer 1

1s2 2s2 2p4

Question 2

What is the hybridisatio of the O in water?

What is its geometry?

What is the bond angles

How many hybrid orbitals?

Answer 2

1. SP3
2. Tetrahedral
3. 104 - 110
4. 4

Question 3

What is the hybridisation of the O in a carbnyl group?

Bond angles

Geometry

hybrid orbitals

Answer 3

1. trigonal planar
2. 120
3. sp2
4. 3

Question 4

What is less likely to be protonated N or O? Why?

Answer 4

There is a higher EN of O therefore the O pulls its lone pair of electrons closer to its nucleus therefore less available for bonding

Question 5

What are the rules of atomic orbitals?

Answer 5

1. The number of molecular orbitals is equal to the number of combined atomic orbitals
2. Bonding molecular orbitals have less energy than parent orbitals (due to stable molecule forming). Antibonding molecular orbitals have more energy than parent atomic orbitals
3. Electrons occupy molecular orbitals in order of increasing engy
4. Atomic orbitals combine with ech other to form molecular orbitals more effectivly if they have similar shape and energy

Question 6

How do you determine bond order?

Answer 6

Bond order = (e-s in bonding MO - e- in AB MO) / 2

e.g. H2 = 1

Question 7

Draw the molecular orbitals or O2 including AB

Answer 7

(σ1s)²(σ*1s)²(σ2s)²(σ*2s)²(σ2p)²(π2p)4(π*sp)²(σ*2p)

Sigma before pi if Ne, O or F, otherwise pi before

Question 8

What is HOMO and LUMO

Answer 8

highest occupied molecular orbital

lowest unocupied molecular orbital

Question 9

What charge is an up or down spin

Answer 9

up = +ve

down = -ve

Question 10

How do you calculate multiplicity of energy levels (M)?

Answer 10

M = 2S + 1

S= sum of valacne electrons in HOMO (+1/2 -1/2)

Question 11

What is M for the following?

Answer 11

Question 12

Complete the table and name the species

Answer 12

Question 13

What molecule is paramagnetic and why?

Answer 13

Oxygen as diradical

Question 14

What happens to the acidicty of an alcohol as you increase carbon chain?

Answer 14

decreases as les soluble

Question 15

What is more singnifacnt in terms of biology activity - a alcohol group or amino group?

Answer 15

Amino - loss of an alocohol does not tend to affect biological activity

Question 16

What is an alcohol called with 2 or 3 -OHs

What is a hydrocarbon with more than 3 -OHs called

Answer 16

diols, triols, polyols

Question 17

What are some properties of glycorls?

Answer 17

• High bpt
• sweet tasting
• viscous
• water micsible
• hydroscopic

Question 18

What is a stronger acid alcohol or phenol. Why?

Answer 18

Phenol - due to delocalisation of the negtaive charge on the conjugate base

Question 19

What else stabilises the phenoxide ion?

Answer 19

EWG in -O or -P position. This increases its acidity

Question 20

What are acidic phenols used for?

Answer 20

antibacterials

Question 21

Draw a diagram for the ionisation and oxidation of a phenol and state which type of reactino this is

Answer 21

Question 22

What can phenols be used for? exmaplin

Answer 22

As antioxidants

phenoxy radicals tend to dimerise and terminate the radical chain reaction

Question 23

1. How does the polatity of ethers compare to the polarity of their corresponding alcohols?
2. What can they be used for?
3. How do epoxides form? What negative properties can these have and why do they posses them?

Answer 23

1. Less polar - no HBD
2. Anaesthesia
3. In the presence of molecular O2 and UV they form explosive epoxides. 3 membered ring epoxides are exremly reactive due to tortisonal strain

Question 24

Are ketones or aldehydes more commonly found in drug structures? Why?

Answer 24

Ketones

Aldehydes are veyr reactive towards nucleophiles. Their high reactivity can result in cytotoxicity

They are commonly found in the open form of reducing sugars

Question 25

Why are carboxylics acids acidic? What effects do EWGs and EDGs have on their acidity

Answer 25

The acidity of carboxylic acids is due to the efficient resonance delocalisation of the negative charge of the carboxylate anions. * EWG can increase acidity by charge delocalisation. * EDG can decrease acidity by charge localisation.

Question 26

What other factors can effect acidity of carboxylic acids

Answer 26

H-bonding can affect acidity: In the case of salicylic acid, intramolecular H-bonding contributes to the charge delocalisation of the conjugate base of salicylic acid. Intramolecular H-bonding is not possible in the case of aspirin.

Question 27

Why might an alkali be used to react with a carboxykluc acid?

Answer 27

TO make it more water sol (salt)

Question 28

What is the differences between O2 and S

Answer 28

sulphur has:Empty 3d orbital avaiable for bonding, larger atomic radius, lower EN

Question 29

What is more acidic? alcohol or thiol? why?

Answer 29

Thiol as has a larger atom group to delocalise charge

Question 30

What can thiols be used for?

Answer 30

Thiols have a large binding affinity for heavy metals and are therefore used to treat heavy metal poisoning by forming water soluble complexes that can be excreted. Thiols are responsible for the formation of –S-S- bridges by cysteine residues and for the detoxifying properties of glutathione (GSH).