Brainscape's Knowledge GenomeTM

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


See full index

Organic Chemistry > Organic Test 6 > Flashcards

Organic Test 6 Flashcards

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

Why is the enamine formed from a secondary amine instead of an imine? (mechanism difference)

A

There is no acidic hydrogen attached to the secondary amine so the base must deprotonate the carbon and create the enamine C=C bond.

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

In benzoic acid derivatives, how do EWG and EDG stabilize the negative charge?

A

EWG enhance the acid strength wherease EDH deplete the acid strength.

EDG like NO2 are more effective in the ortho/para position than the meta position.

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

How can you identify the carboxylic acid proton in 1H NMR?

A

It will appear as a singlet in the 11-12 range. Very far down field!

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

What is the order of reactivity among:

anhydride, nitriles, acyl chlorides, and esters?

A

Left to right, most to least reactive.

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

What are the rules for naming anhydrides?

What about this example?

A

drop “acid” and add “anhydride”

Propanoic anhydride

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

Which carbonyl will react with only 1 equivalent of HOCH2CH2OH?

A

The aldehyde carbonyl because aldehyde or more reactive than the ketone and an alcohol is not a strong enough nucleophile.

Weak nucleophiles (like alcohols) are selective!!

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

What are the rules for naming assymetrical anhydrides?

A

Name each acid separately, drop “acid” add “anhydride”

acetic 2-chloropropanoic anhydride

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

What are the rules for naming dicarboxylic acids?

What is the name of this example?

A

2-methyl-3-phenylpentanedioic acid.

For straight chain dicarboxylic acids, use the longest chain that contains both carboxyl groups.

Number begining with the carboxyl group that gives the substituents the lowest numbers.

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

What is the difference between base promoted and acid promoted alpha halogenation?

A

With base promoted halogenation, the alpha carbon can not be mono halogenated. As halogen groups are added, the Hydrogen becomes more acidic and picked up by OH

In acidic condition, there can be mono halogenation.

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

What are the IUPAC rules for naming cyclic dicarboxylic acids and carboxylic acids?

What is the name of this example?

A

trans-1,3-cyclopentanedicarboxylic acid

Cyclic dicarboxylic acids: treat the carboxyl group as substituents on the cyclic structure.

Cyclic carboxylic acids: Cycloalkaes with -COOH substituents are generally named as cycloalkanecarboxylic acids.

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

Which is more reactive?

A

The acid chloride is the most reactive carbonyl compound whereas the carboxylic acid is the least.

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

What are the rules for naming acid halides?

What about this example?

A

drop “ic acid” and add “yl halide.” In the cyclic case, drop “carboxylic acid” and add “carbonyl halide”

Propanoic acid–> propanoyl chloride

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

When looking at boiling point of carboxylic acid derivatives, what do we look at specifically?

A

EN of the side group.

(ex: NH2 is less E than OH, therefore NH2 is more stable being positive which contributes to stronger H-bond)

Resonance

(ex: why carboxylic acid has higher BP than alcohol)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What factors affect acidity?

A
  1. Resonance: resonance stabilizes the negative charge so an acidic proton becomes more acidic.
    (ex: CH3CH2OH v. CH3COOH)
  2. Electron withdrawing groups: More EWG means that the carbonyl carbon is more positive and thus less stable.
  3. Electron Donating Groups: More EDG groups donate negative charge to the carbonyl carbon, thus stabilizing it.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do we number ketones for naming purposes?

A

We number the longest chain that includes the carbonyl and number from the end closest to the carbonyl.

In cyclic ketones, the carbonyl carbon is assigned the number 1.

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

When the coupling constant on a 1H NMR is small, what does that say about the compound?

A

In this case, the alkene Hydrogens have a small coupling constant so the compound is not a cis/trans isomer. With a larger coupling we can find a cis or trans double bond.

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

Acetone

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

What are the rules for naming nitriles?

And this example?

A

Add “nitrile” to IUPAC name, or in carboxylic acids and cyclic alkanes, replace “carboxylic acids” with “carbonitrile”

trans-2-chlorocyclohexanecarbonitrile

If using an acids common name, drop “ic” and add “onitrile”

(ex: acetonitrile)

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

What are the rules for naming esters?

And this example?

A

Write name of the alkyl group coming from the O and then name as derivative of acid. Drop “ic acid” and add “ate

2-hydroxypropyl acetate

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

What is the effect of ring strain on IR frequency?

A

Increasing ring strain increases IR frequency (less stable)

17
Q

What are the rules for naming amides?

What is the name of this?

A

Unsubstituted:

Replace “ic” with “amide” or in cyclic, “carboxamide”

Substituted: (NR2 , NHR):

Name group bonded to N, preceed with N, and then follow rules like above.

N,N,3-trimethylbutanamide

18
Q

How is the wittig reagant formed?

A

Triphenyl phosphine nucleophilically attacks an alkyl halide. Works via an SN2 substitution so the alkyl halide must be primary.

19
Q

What is this?

A

a malonic ester. “di-ester”

20
Q

What 3 factors affect reactivity of carboxylic acid derivatives?

A
  1. Basicity (stability of LG):

Chlorine is stable negative, a negative ester is a resonance stabilized base. OH and NH2 are less stable bases. (NH2 is a very strong base)

  1. Resonance:

In an acyl chloride, Cl withdraws E density by induction. In anhydridge, Each carbonyl shares some E density from O group, so less negative. Finally, between carboxylic acids and amido groups, O- is more stable negative than NH, so O- withdraws more E density.

  1. Steric:

These are only sometimes a factor. WHEN DEALING WITH SAME COMPOUND

21
Q

What is the result on UV spec of adding more R groups to similar structures?

A

Adding R groups and increasing conjugation INCREASES the wave length.

22
Q

What are the different levels of acidity of the alpha carbons??

A

pka= 20

pka= 24

pka= 13

pka= 11

pka= 9

23
Q
A

Propiophenone

25
Q

In order for a weak nucleophile like water to attack a carbonyl carbon, what must happen?

A

The oxygen must be protonated to make the carbon even more positive.

26
Q

What is the reactivity of aldehydes vs. ketones?

A

Aldehydes are more reactive because they have a more positive carbon.

27
Q

What breaks down the acetal?

(HOCH2CH2OH)?

A
28
Q

What is true of the solubility in water of different carboxylic acid compounds?

A

Carboxylic acid more soluble than alcohol (more H bonding)

Longer chained carboxylic acids are less soluble in water.

More than 6 carbons, carboxylic acid compounds are minimally soluble.

29
Q

What is the difference in reaction between an acyl carbonyl and a ketone/aldehyde carbonyl?

A

Acyl carbonyl: sp2-> sp2 (nucleophilic substitution)

Ketone/aldehyde: sp2 -> sp3 (nucleophilic addition

30
Q

What determines the stability of an aldehyde or ketone?

A

The positivity of a carbonyl carbon. A less positive carbonyl carbon is more stable.

From left to right, these carbonyls are decreasing in stability due to loss of EDG and gain of EWG.

31
Q

What are the intermediates formed in the Wittig reaction?

A

A betaine and a 4-membered ring called oxaphosphetane. The 4-membered ring collapses

33
Q

What is the effect of conjugation on IR frequency?

A

Conjugation lowers frequency.

34
Q

How do you name nitriles as substituents?

What about in this example?

A

name it a “cyano” group

3-cyanobutanamide

36
Q

What is the IUPAC rule for naming ketones?

A

replace the final “e” in the alkane with “one”

for example, pentane becomes pentanone

38
Q

What is an acetal?

A

A protected carbonyl from a reaction with ROH and H+

39
Q

Evidence of what?

A

Para- benzene

40
Q

When do you use Clemmenson reactiong (ZnHg/HCl/H20)

vs. Wolf-Kischner
(1. NH2NH2/H+/ 2. KOH/ DMSO or heat)

A

Use clemmenson for:

R-X. It proceeds via E2/SN2

Use W-K for:

C=C so that it doesn’t undergo electrophilic additon (E2)

42
Q

Which has a larger melting point?

A

The compound on the right has a larger melting point due to better packing.

43
Q

When using LDA to alkylate alpha carbons, what do we have to remember?

A

LDA is a bulky base so it will attack less substituted alpha carbon (given the choice)

Also, LDA doesn’t work with aldehyde because can fit to attack the carbonyl directly.

44
Q

How do you name ketones and aldehydes as substituents?

A

ketone: use prefix “oxo”

CHO group: “formyl”

45
Q

What are the rules for naming aromatic carboxylic acids?

What is the name of this example?

A

Ar-COOH compounds are named as derivatives of benzoic acids.

This example is ortho-2-hydroxybenzoic acid

46
Q
A

Acetophenone

47
Q

What are the IUPAC rules for naming carboxylic acids?

What is the name of this example?

A

3-methylbutanoic acid.

Carboxylic acid takes priority over any other compound.

Drop the “e” in the alkane name and add “oic acid”

Number starting with the carboxyl group

48
Q

What is the IUPAC rule for naming aldehydes?

A

replace the final “e” of the alkane with “al”

The aldehyde carbon is number one.

If attached to a ring, “carbaldehyde” is used.

49
Q

What has a higher boiling point an amide or a carboxylic acid?

A

An amide! The hybrid is more stable positive and has a more powerful hydrogen bond.

50
Q

What is the order from high to low of BP for the following:

butane

carboxylic acid

amido

methyl ester

nitrile

A

Most to least acidic:

amido

carboxylic acid

alcohol

nitrile (about equal to alcohol)

methyl ester

butane

51
Q

What reagant will turn this into a carboxylic acid?

A

It will protonated and can later be turned into a carbonyl chloride if more reactions are necessary.

Organic Chemistry (8 decks)

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