Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pharmaceutical Chemistry > Exam I: EWG, EDG, Acid-Base Chem > Flashcards

Exam I: EWG, EDG, Acid-Base Chem Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

What effects do functional groups have on drugs activity in the body?

A
  1. Drug transport through the body
  2. Mechanism to bind to receptors
  3. How it causes a biological response
  4. How it undergoes metabolism
  5. How it is excreted
  6. Drug stability during storage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Tautomerization is the equilibrium reaction between a ____ their less stable ____ .

A

Tautomerization is the equilibrium reaction between a Keto their less stable Enol.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the field effect?

A

Polarization experience through space rather than bonds

ex. An oxygen atom on a carbonyl can pull electron density from a nitrogen a few carbons away

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the inductive effect?

A

Polarization due to the electronegativity difference between bonded atoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How can an alkyl group contribute to delocalizing a neighboring positive charge? What is this process called?

A

An alkyl can break a hydrogen bond so that the newly freed electrons can stabilize a cation

This is called hyperconjugation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Alkyl groups are EWG or EDG? Why?

A

Alkyl groups are electron donating groups through induction.

There is a partial negative charge on the carbon due to its pull on electron density from bonded hydrogen atoms.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

-CH3, -CH2, CH, C-R. Which group would be the best electron donating group?

A

-CH3 because it has the greatest number of hydrogen bonded to it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

-NO2, -F, CO2H. Put in order from most to least EWG.

A

-NO2 > CO2H > F

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Would a ketone or a carboxylic acid have greater electron withdrawing potential? Why?

A

A ketone would have greater electron withdrawing potential.

Carbonyls attached to electronegative heteroatoms have weaker withdrawing power due to resonance which decreases the positive charge that builds on the carbonyl carbon.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Put the halogens in order of withdrawing power (-I, -Br, -F, -Cl). Explain this order.

A

-F > -Cl > -Br > -I

Larger atoms have lower electronegativity due to less shielding of the positive charge of the nucleus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What type of environment do drugs exert their biological activity?

A

Aqueous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Bronsted and Lowry acid and base

A

Acid - Donates proton (hydrogen)

Base - Accepts proton (hydrogen)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Do strong or weak hydrogen bonds make strong acids? What heteroatoms typically form the weakest bonds with hydrogen?

A

Weak hydrogen bonds make stronger acids

Oxygen, sulfur, nitrogen and phosphorus tend to form the weakest bonds to hydrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

If a compound (not an atom) is not an acid nor a base then it is considered positive, negative or neutral?

A

Neutral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Lewis acids and bases

A

Lewis acid - electron acceptor (electrophile)

Lewis base - electron donor (nucleophile) - must have a lone pair

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the equation for Ka?

A

Ka = [H+][A-]/[HA]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the equation for pKa?

A

pKa = -log(Ka)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Highest possible Ka value? Lowest possible pKa value?

A

Ka = 1 for the dissociation of hydronium ion (H3O+)

pKa = 0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

High Ka –> Strong or weak acid?

A

High Ka = strong acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Low pKa –> Strong or weak acid?

A

Low pKa = strong acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the Kw of autoionization of water forming H3O+ and OH-?

A

1 x 10^-14

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the three equations for gibbs free energy discussed? Two are ΔG = and one is pKa =.

A

ΔG = -RTlogKa

ΔG = Total energy of products - Total energy of reactants

pKa = ΔG/RT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Value for R gas constant. Include units.

A

1.987 cal/mol⋅K

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Unit for temperature in gibbs free energy equations. Conversion to this unit.

A

Kelvin (K)

T(°C) + 273.15 = T(K)

25
Q

Gibbs free energy and pKa are _____ related?

A

Gibbs free energy and pKa are proportionally related

↑ ΔG = ↑ pka

26
Q

F3CO2H vs H3CO2H. Which is a stronger acid?

A

F3CO2H is a stronger acid

27
Q

In water what are the ranges for pka and pkb?

A

0 - 14

28
Q

High kb = Strong or weak base?

A

Strong base

29
Q

Low pkb = Strong or weak base?

A

Strong base

30
Q

pH can be compared to pka and pkb. (True/False)

A

False

pH can only be compared to pKa

31
Q

If pkb (base) = 4, what is the pka of the conjugate acid?

A

pka + pkb = 14 therefore, pka = 10

32
Q

In a molecule there are two substituents. Group 1 (pka = 9) - Group 2 (pka 4). Which group would donate a proton first?

A

Group 2 because it is more acidic

33
Q

In a molecule there are two substituents. Group 1 (pkb = 5) - Group 2 (pkb = 10). Which group would gain a proton first?

A

Group 1 because it is more basic

34
Q

What is a salt?

A

A salt forms when an acid reacts with a base

Ionized form

35
Q

Why are a vast majority of drugs in the salt form?

A

Charged compounds typically have good water solubility

Usually have a crystalline structure

Good bioavailability

36
Q

What is the henderson-hasselbalch equation?

A

pka = pH + log[HA]/[A-}

37
Q

What is the percent ionization equation? Define what an ionized molecule is.

A

%ionization = [ionized]/[ionized+nonionized]

The ionized molecule has a charge does not matter if it is the acid or base form

NH4+ (Ionized acid) - OH- (ionized base)

38
Q

What equation is used to find the concentrations of the ionized and nonionized molecules?

A

Henderson-hasselbalch equation

pka = pH + log[HA]/[A-}

39
Q

What are the steps to find the percent of acetic acid ionized at pH 5? Given acetic acid pka = 4.

A
  1. Write down the equation to visual the ionized form
    AcOH –> AcO- + H+
  2. Use pka = pH + log[HA]/[A-} to find the concentrations
    AcOH/AcOH- = 1/10
  3. Calculate the percent ionization
    10/1+10 x 100% = 90.9%
40
Q

What are the pH within the following body compartments: stomach, intestine (duodenum), intestine (lower ileum), circulating fluids (i.e. plasma, CSF)?

A

Stomach - pH 1

Intestine (duodenum) - pH 5

Intestine (lower ileum) - pH 8

Circulating fluids - pH 7

41
Q

pka of water H-OH without any added groups?

A

pka 14

42
Q

pkb of ammonia H-NH2 without any added groups?

A

pkb 5

43
Q

How do electron withdrawing groups affect acid-bases?

A

EWG can stabilize conjugate bases of an acid so the acid becomes stronger (lower pKa)

44
Q

Put these EWG in order from strongest. Carbonyl, sulfonyl, aryl.

A
  1. Sulfonyl SO2
  2. Carbonyl CO
  3. Aryl = phenyl group
45
Q

Why is aniline (benzene with -NH2) a weaker base than ammonia (NH3)?

A

EWG delocalize lone pairs weakening the basicity of aniline

46
Q

Why does acetamide behave as an acid?

A

Acetamide H3C C=O NH2

Carbonyl delocalizes the lone pair on the nitrogen giving it a positive charge through resonance

47
Q

Use the pka-pka scale to determine the pka or pkb of ph-o-ph.

A

This compound is neither an acid nor a base because there is no hydrogen to donate or any available lone pairs to accept a hydrogen.

48
Q

Reference notes on how to determine pka of a compound that must be converted to conjugate acid or base to solve.

A

Beneath “how could you predict the pka for this compound?”

Note: to predict pka/pkb the compound must be neutral (no charge)

49
Q

Why are imines (H3C C=NH CH3) less basic than amines (-NH2)?

A

Sp2 orbitals are smaller than sp3 orbitals

Sp2 orbitals have greater shielding of the positive charge of the nucleus

Imines have a greater hold on their electrons than amines

50
Q

Is N(CH3)3 an acid or a base? Compare to ph-o-ph

A

This is a base.

Note that nitrogen is not a highly electronegative atom so a hydrogen atom can be added to nitrogen and acquire a positive charge

ph-o-ph is a neutral compound because oxygen is too electronegative to donate electrons to a hydrogen and acquire a positive charge

51
Q

Effect of H or Alkyl (-CH3) to pka? As first and second group.

A

H or Alkyl (-CH3) groups do not have an affect on pka

H2O and Ethanol have the same pka

52
Q

Effect of aryl, C=C (double bond), C=N, N=N, C (triple bond)? As first and second group.

A

First group - 5

Second group - 2

(toward pka end) = more acidic

53
Q

Effect of C=O or Ar C=O? As first or second group.

A

First group - 10

Second group - 5

(toward pka end) = more acidic

54
Q

Effect of SO2 or ArSO2? As first or second group.

A

First group - 15

Second group - 7

(toward pka end) = more acidic

55
Q

pka/pkb of aniline

A

pkb 10

56
Q

pka/pkb of MeSo2-NH2

A

pka 9

57
Q

In amidine, which nitrogen is more basic (imine or amine)?

A

The imine nitrogen is the stronger base because resonance stabilizes the conjugate acid

See note for a visual or write down the reaction

58
Q

If an EWG like a carbonyl is added to the imine nitrogen in amidine, what would happen to the pkb? Increase or decrease?

A

The nitrogen would become less basic so the pkb would increase

Pharmaceutical Chemistry (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions