Deck 24: Amines and Heterocycles

Question 1

Exhibit 24-4
Refer to the reaction below to answer the following question(s):
Refer to Exhibit 24-4.This reaction is an example of:

A)a Curtius rearrangement
B)a Hofmann elimination reaction
C)a Gabriel synthesis
D)a Hofmann rearrangement

Answer 1

a Hofmann rearrangement

Question 2

Exhibit 24-8
Refer to the data below to answer the following question(s):
Triclocarban is a disinfectant prepared from 3,4-dichloroaniline and 4-chlorophenylisocyanate.
Refer to Exhibit 24-8.Propose a mechanism for the reaction of 3,4-dichloroaniline and 4-chlorophenylisocyanate to yield Triclocarban.

Answer 2

Question 3

Name:

Answer 3

methyl 2-aminobutanoate

Question 4

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Question 5

Exhibit 24-3
Refer to the Table of pK_as below to answer the following question(s):
pK_as of Some Arylammonium Ions Y
pK_a
−H
4.63 1.74
−NH₂
6.15
Refer to Exhibit 24-3.Explain the difference in acidity between p-aminoanilinium ion and anilinium ion.Use both words and structures.

Question 6

Exhibit 24-8
Refer to the data below to answer the following question(s):
Triclocarban is a disinfectant prepared from 3,4-dichloroaniline and 4-chlorophenylisocyanate.
Refer to Exhibit 24-8.Prepare 4-chlorophenylisocyanate from toluene.

Question 7

Name:

Question 8

Exhibit 24-2
Consider the reaction below to answer the following question(s).
Methamphetamine can be synthesized by reacting phenyl-2-propanone with methylamine in the presence of H₂/Ni.
Refer to Exhibit 24-2.Intermediate A is an example of:

A)an imine
B)an enamine
C)an iminium ion
D)an imide

Question 9

Exhibit 24-3
Refer to the Table of pK_as below to answer the following question(s):
pK_as of Some Arylammonium Ions Y
pK_a
−H
4.63 1.74
−NH₂
6.15
Refer to Exhibit 24-3.Explain the difference in acidity between p-cyanoanilinium ion and anilinium ion.Use both words and structures.

Question 10

Exhibit 24-2
Consider the reaction below to answer the following question(s).
Methamphetamine can be synthesized by reacting phenyl-2-propanone with methylamine in the presence of H₂/Ni.
Refer to Exhibit 24-2.Identify the nucleophile in the initial reaction of phenyl-2-propanone to yield intermediate A.

Question 11

Name:

Question 12

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Question 13

Exhibit 24-3
Refer to the Table of pK_as below to answer the following question(s):
pK_as of Some Arylammonium Ions Y
pK_a
−H
4.63 1.74
−NH₂
6.15
Refer to Exhibit 24-3.Based on the pK_as for their corresponding ammonium ions,which arylamine above is the strongest base?

Question 14

Exhibit 24-8
Refer to the data below to answer the following question(s):
Triclocarban is a disinfectant prepared from 3,4-dichloroaniline and 4-chlorophenylisocyanate.
Refer to Exhibit 24-8.Prepare 3,4-dichloroaniline from benzene.

Question 15

Exhibit 24-2
Consider the reaction below to answer the following question(s).
Methamphetamine can be synthesized by reacting phenyl-2-propanone with methylamine in the presence of H₂/Ni.
Refer to Exhibit 24-2.Although the yield of methamphetamine is good,some unreacted phenyl-2-propanone remains after the reaction is complete.Describe how methamphetamine can be separated from phenyl-2-propanone.

Question 16

Rank the following compounds in order of increasing basicity.Label the least basic compound "1" and the most basic compound "4".Place the number corresponding to the compound's rank in the blank below the compound.

Question 17

Name:

Question 18

NaOH,H₂O
f.HNO₃,H₂SO₄

Question 19

When a THF solution of phenyl-2-propanone and bromobutane is treated with 50% aqueous NaOH,poor yields of 3-phenyl-2-heptanone result.However,when a small amount of benzyltriethylammonium chloride is added to the reaction mixture,the yield of 3-phenyl-2-heptanone increases to 90%.Explain these results.

Question 20

Exhibit 24-4
Refer to the reaction below to answer the following question(s):
Refer to Exhibit 24-4.Draw arrows on the structures provided below which show electron flow in the complete stepwise mechanism for the reaction above.

Question 21

Which of the following methods of preparation of amines can be used to prepare primary,secondary,and tertiary amines?

A)reduction of a nitrile
B)Gabriel synthesis from an alkyl halide
C)reduction amination of a ketone
D)Hofman rearrangement of an amide
E)None of these methods is applicable to all types of amines.

Question 22

Draw the structures for each of the intermediates in the boxes provided for the synthesis below.

Question 23

Describe the importance of the formation of arenediazonium salts.

Question 24

Which of the following would best represent the form of ethylamine (pK_a) at physiological pH?

A)CH₃CH₂NH₃⁺
B)CH₃CH₂NH₂
C)CH₃CH₂NH^-
D)a combination of a and b

Question 25

An unknown substance produced the following spectrum. This unknown is likely to be a:

A)primary amine
B)secondary amine
C)tertiary amine
D)amide

Question 26

Name the following substance.Atoms other than carbon and hydrogen are labeled.

Question 27

Classify the following amine.Atoms other than carbon and hydrogen are labeled.

A)primary
B)secondary
C)tertiary
D)quaternary

Question 28

Write the equation for the reaction represented by the pK_a of methyl amine.

Question 29

Propose a structure that is consistent with the following spectral data:
MS:
M⁺ at 73
IR:
3350 cm−¹ (weak,single band)
¹H NMR:
δ1.05 (br s,1H),δ1.15 (t,6H),δ2.65 (q,4H)

Question 30

​Draw the mechanism for the Hofmann rearrangement of acetamide to acetamine.

Question 31

At which pH will a solution of a 0.00050 M solution of aniline (pK_a = 4.63) contain the greatest amount of the neutral species?

A)2.74
B)4.63
C)7.31
D)9.90

Question 32

Which of the following methods of preparation of amines results in an amine with one less carbon atom than the starting material?

A)reduction of a nitrile
B)Gabriel synthesis from an alkyl halide
C)reductive amination of a ketone
D)Hofman rearrangement of an amide

Question 33

Draw the product of the reaction of the following substance with 1) LiAlH₄ in ether,2) H₂O.From what alkyl bromide could this substance be produced when reacted with NaCN? Atoms other than carbon and hydrogen are labeled.

Question 34

Which of the following is not classified as a heterocycle?

A)
B)
C)
D)
E)c and d

Question 35

​Draw the mechanism of the reductive amination of 2-butanone in the presence of ammonia and hydrochloric acid.

Question 36

Compared to pentylamine,pentane is

A)more soluble in water.
B)has a higher boiling point.
C)is less basic.
D)more offensive in terms of odor.

Question 37

What is the percentage of neutral species in a 0.00500 M solution of pyridine at pH 9.50? pK_a of pyridine is 5.25.

A)25%
B)75%
C)50%
D)nearly 100%
E)close to 0%

Question 38

The pK_a of diethylammonium ion is 10.98.What is the pK_b of diethylamine?

A)3.02
B)14.00
C)24.98
D)7.00

Question 39

Which of the following is not a valid comparison of the spectral data for alkyl amines and alkyl alcohols?

A)IR: strong absorptions > 3000 cm^-1.
B)MS: peaks due α-cleavage
C)(¹³C NMR: adjacent carbon signal shifted downfield relative to an alkane)
D)(¹H NMR: proton bonded to the heteroatom appears over a wide range)
E)All are valid comparisons between the spectral data of amines and alcohols.

Question 40

The amino acid phenylalanine has the structure below. Which of the following is the best representation of this acid at pH 7.3?

A)
B)
C)
D)

Question 41

​Draw the mechanism of the Sandmeyer reaction that converts o-methyl aniline to o-bromotoluene.