Amines Flashcards

1
Q

What is an amine?

A

A molecule in which nitrogen is bound to one, two or three organic groups(amines are derivatives of ammonia)

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2
Q

Alkaloids are….

A

An important group of biologically active amines

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3
Q

Why do plants synthesize alkaloids?

A

To protect them from being eaten by insects or other animals

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4
Q

Many drugs if addiction are classified as ….

A

Alkaloids

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5
Q

Give examples to describe the biological activity of amines

A

Dopamine is a neurotransmitter

Epinephrine is a bio regulator

Niacin, vitamin b6, is an amine

Alkaloids: nicotine, morphine, cocaine

Amino acids

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6
Q

Describe each class of amines

A

Primary- has one alkyl group bonded to nitrogen (RNH2)

Secondary- has two alkyl groups bonded to the nitrogen (R2NH)

Tertiary- has 3 alkyl groups bonded to the nitrogen(R3N)

Quartenary- has 4 alkyl groups bonded to the nitrogen and nitrogen bears a positive charge (R4N+)

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7
Q

Describe aromatic amines

A

The amino group is bonded to a benzene ring

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8
Q

What is the parent compound called of an aromatic amine?

A

Aniline

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9
Q

What are heterocyclic amines?

A

Compounds in which the nitrogen atom occurs as part of a ring

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10
Q

The Herero lyric nitrogen is always numbered as…

A

Position 1

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11
Q

Describe the structure of amines

A

Nitrogen is sp3 hybridized with a lone pair of electrons

The angle is less than 109.5 degrees

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12
Q

Compare the boiling point of amines to corresponding alcohols and ethers and give a reason for the

A

Nitrogen is less electronegative than oxygen so N-H is less polar than O-H.

This causes amines to have weaker hydrogen bonds than corresponding alcohol but amines have higher boiling points than those of the corresponding ether

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13
Q

Why do tertiary amines have a lower boiling point than primary and secondary amines?

A

Tertiary amines cannot hydrogen bond so they have lower boiling points than primary and secondary amines

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14
Q

Describe the hydrogen bonding activity in primary, secondary and tertiary amines

A

Primary and secondary- hydrogen bond donor or acceptor

Tertiary- hydrogen bond acceptor only

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15
Q

Describe the odor of amines

A

Most amines smell like rotting fish. Some diamonds are particularly pungent

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16
Q

Describe the solubility of amines

A

All amines, including tertiary amines form hydrogen bonds with hydroxylic solvents like water and alcohols

Branching increases solubility

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17
Q

Describe solubility of amines in water

A

Small amines, less than 6 carbons are relatively soluble in water

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18
Q

_________ ________ are usually stronger bases than ammonia

A

Alkyl amines

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19
Q

Why are amines also nucleophiles/lewus bases?

A

It’s lone pair of non bonding electrons form a bond with an electrophile

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20
Q

Why are amines able to act as bronsted Lowry bases?

A

By accepting a proton from an acid (lone pair of electrons on nitrogen can accept a proton from an acid)

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21
Q

What is the pKb of ammonia?

A

4.74

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22
Q

How do the presence of alkyl groups affect solvation/basicity?

A

Increase in alkyl groups decreases solvation of ion, so secondary and tertiary amines are like primary amines in basucity

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23
Q

How can ammonium salts be obtained?

A

Protonation of an amine give an ammonium salt

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24
Q

What are the 2 types of ion in ammonium salt

A

The protonated amine cation(an ammonium ion)

The anion derived from the acid

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25
Q

Describe the solubility of ammonium salts in no polar organic salts

A

Only slightly soluble in nonpolar solvents

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26
Q

How soluble are ammonium salts in water?

A

Much more soluble in water than parent amines

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27
Q

Formation of a soluble salt is one _________ ________ _____ _______for amines

A

Characteristic functional group tests

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28
Q

What can formation of amine salts be used for?

A

Used to isolate and characterize amines

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29
Q

How do ammonium salts react in dilute aqueous acids?

A

These amines(with more than 6 carbons and are insoluble in water) form their corresponding ammoniumsalts and they dissolve.

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30
Q

How can cocaine be converted back to its volatile free base form for smoking from cocaine hydrochloride form?

A

Treat the cocaine hydrochloride with Sodium hydroxide and extracting it into ether

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31
Q

How is cocaine usually smuggled and snorted?

A

In the form of hydrochloride( adding HCl to cocaine)

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32
Q

How can imines be formed?

A

Adding ammonia and primary amines to aldehydes to ketones

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33
Q

How can an oxide be formed?

A

Ketone or aldehyde added to OH-NH2

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34
Q

How can a hydrazine be formed?

A

Ketone or aldehyde added to NHR-NH2

35
Q

What are the 2 most generals reactions of alkyl amines?

A

Alkylation and acylation

36
Q

How can alkylation of amines occur?

A

Addition of alkyl halides to primary, secondary or tertiary amines

37
Q

What type of reaction is the formation of amides using acylation of amines?

A

Nucleophilic acyl substitution

38
Q

What does the acylation of amines create?

A

Amides

39
Q

Explain the acylation of amines

A

Primary and secondary amines(but not tertiary) react with acid acid halides or acid anhydrides to form amides

40
Q

When the amino group of aniline is acylated the resulting amide is _________ and _____________ directing

A

Activated

Ortho para

41
Q

Addition of acid chloride to an aniline forms …

A

An acetanilide

42
Q

How can acetanilide be further substituted?

A

Addition of acidic(and mild oxidizing)nreagents

E.g. dilute HNO3 and H2SO4

43
Q

How can an acyl group be removed from acetanilide?

A

Acidic or basic hydrolysis

44
Q

Explain the formation of alkyldiazonium salts

A

Primary amines react with nitrous acid(HNO2) to form alkyldiazonium salts

45
Q

What happens to diazonium salts and why?

A

Diazonium salts are unstable so they decompose into carbocations and nitrogen

46
Q

How can an aromatic compound be used to form. and diazotized?

A
  1. Addition of HNO3 and H2SO4 to form nitrobenzene
  2. Addition of Fe, HCl and OH- to nitrobenzene to form aniline
  3. Addition of NaNO2, HCl to form arenediazonium
47
Q

Why are arenediazonium formed?

A

To convert an activated group can be converted to a wide variety of functional groups

48
Q

Arenediazonium reacts with warm H30+, what is formed?

A

Phenols

49
Q

Arenediazonium reacts with CuCl(Br), what is formed?

A

Aryl halides Ar—Cl(Br)

50
Q

An arenediazonium reacts with CuCN, what is formed?

A

Benzonitriles Ar—CN

51
Q

An arenediazonium reacts with HBF4(KI), what is formed?

A

Aryl halides Ar—F(I)

52
Q

What chemical is used for the deamination of arenediazonium salts?

A

H3PO2

53
Q

Arenediazonium reacts with H3PO2, what is formed?

A

Ar-H normal arene/deamination occurs

54
Q

Arenediazonium reacts with an arene, what is formed?

A

Azo dyes(Ar—N=N—Ar)

55
Q

Explain the formation of N-Nitrosamines

A

Secondary amines react with nitrous acid HNO3

56
Q

Secondary N-Nitrousamines are ______ and have been shown to be _______________ in lab animals

A

Stable

Carcinogenic

57
Q

What are sulfonyl chlorides?

A

The acid chlorides of sulfonic acids

58
Q

Like acyl chlorides, ________ ____________ are strongly ___________

A

Sulfonyl chlorides

Electrophilic

59
Q

What are sulfonamides?

A

Amides of sulfonic acids

60
Q

How are sulfonamides formed?

A

Primary and secondary amines attack a sulfonyl chloride and displaces chloride ion to give an amide

61
Q

What are the sulfa drugs?

A

A class of sulfonamides used as antibacterial agents

62
Q

List the ways in which amines can formed

A

Reductive amination of aldehydes or ketones

Reduction of nitriles

Reduction of amides

Reduction of nitrobenzene

Alkylation of ammonia or alkylamine

63
Q

How to produce primary amines using thecondensation of hydroxylamine?

A

Condensation of hydroxylamine (no alkyl groups). Along with aldehyde or a ketone( includes benzaldehyde)

followed by the reduction of oxime which can be done with LiAlH4 or NaBH3CN

64
Q

What can be used to reduce oxime?

A

LiAlH4 or NaBH3CN(sodium cyanoborohydride)

65
Q

How can amines react bee synthesized from an aldehyde or ketone?

A

Synthesized from an aldehyde or ketone by reaction with ammonia or an amine in the presence of a reducing agent

66
Q

Describe(not give the steps) about the reduction of nitriles to a primary amine

A
  • This is a 2 step mechanism of an SN2 reaction between an alkyl halide or tosylate with cyanate is followed by reduction
  • Nitrile is a good SN2 reaction
67
Q

Describe the steps of the reduction of nitriles to primary amines

A
  1. (Primary or secondary) Halide or tosylate reacts with a cyanate ion)
  2. Nitrile is formed and reduced by LiAlH4 or H2 and catalyst
  3. Carbon is added between amine group and R group, forming a primary amine
68
Q

Give the steps to reduce amides/carboxylic acid to amines

A
  1. React carboxylic acid with SOCl2 and NH3 to form an amide

2. Amide reacts with LiAlH4, ether and water, this gives a primary amine

69
Q

Aside from acyl substitution of carboxylic acids, how can an amide be produced for reduction to an amine?

A

Acylation of NH3 followed by reduction with LiAlH4

70
Q

What is the Hoffman rearrangement of Amides?

A

In the presence of a strong base, primary amides react with chlorine or bromine to form shortened amines, with the loss of the carbonyl atom

71
Q

What is Hoffman rearrrangement used to do?

A

Synthesize primary and aryl amines

72
Q

How are arylamines prepared?

A

By nitration of an aromatic starting group, followed by reduction of a nitro group

Reduction step can be carried out in different ways depending on the circumstances

73
Q

Using the reduction of nitrobenzene, how can m-Nitrobenzaldehyde be converted to m-Aminobenzaldehyde

A

M-Nitrobenzenaldehyde

  1. SnC,2, H3O+
  2. NaOH

M-aminobenzaldehyde

74
Q

What type of reaction is alkylamine synthesis?

A

SN2 reaction

75
Q

Explain alkylation of ammonia

A

NH3 reacts with alkyl halide(SN2) to displace the halogen

NaOH that creates a primary amine

76
Q

In alkylation, what is the product of a primary amine with an ally halide and then NaOH?

A

Secondary amine

77
Q

What are the reactants and products of the alkylation of a secondary amine?

A
  1. Secondary amine and alkyl halide(SN2 reaction)

2 NaOH

This forms a tertiary amine

78
Q

Explain the reaction of a tertiary amine to form a quartenary amine?

A

Tertiary amines react(SN2) with alkyl halides

Halogen displaced

Quaternary amine

79
Q

Explain the results of the nitrous acid test for each type of amine

A

Primary amines can react to form a diazonium salt which then loses N2 gas

Secondary amine, N-nitroso compound is formed and separates from the aqueous solution as a yellow or orange liquid. No N2 gas formed

No reaction with tertiary amines

80
Q

Describe the results of Hinsberg test

A

Primary amines produce sulfonamides that are soluble in basic solution

Secondary amines produce sulfonamides that are insoluble in basic solution

Tertiary amines fail to react with benzene sulfonyl chloride

81
Q

How can a primary aliphatic amine test be differentiated from a primary aromatic amines?

A

Primary aromatic amines can be distinguished from primary aliphatic amines by their ability to undergo diazotization and coupling with phenol to form a dye

82
Q

Primary and secondary amines react with sulfonyl chloride to…

A

Displaces chloride to form a sulfonyl amide

83
Q

What are the purpose of sulfa drugs?

A

Class of sulfonamides for antibacterial drugs