Download 06. Alcohols. Phenols. Ethers

LECTURE № 6
Theme: Alcohols.
Phenols. Ethers.
associate. prof. Ye. B. Dmukhalska, assistant. I.I. Medvid
Plane.
1. Alcohols: Classification, nomenclature.
2. The methods of extraction of monohydroxyl alcohols.
3. Monohydric alcohols: classification, isomery, physical,
chemical properties of monohydroxyl alcohols.
4. Di-, tri- and polyhydroxyl alcohols.
5. Thioalcohols.
6. Ethers (simple ethers).
7. Enols. Aminoalcohols.
8. The methods of extraction of mononuclear phenols
9. Mononuclear phenols: the nomenclature, isomerism,
physical, chemical properties
10. Di-, tri- and polynuclear phenols: Chemical properties
11. Aminophenols
12. Aromatic carboxylic acids
Classification of alcohols.
All alcohols, а principle, can be divided into
two broad categories i.е. aliphatic alcohols
and aromatic alcohols.
1. Aliphatic alcohols. Alcohols in which the
hydroxyl group is linked an aliphatic carbon
chain are called aliphatic alcohols.
For example,
Methyl alcohol
alcohol
Methanol
Ethyl alcohol
Ethanol
Isopropyl
2-Propanol
2. Aromatic alcohols. Alcohols in which the hydroxyl group is present in the
side chain of an aromatic hydrocarbon are called aromatic For example.
phenylmethanol
(benzyl alcohol)
2-phenylethanol
(-phenylethyl alcohol)
Alcohols are further classified as monohydric, dihydric, trihydric and
роlyhydric according as their molecules contain one, two, three, or
many hydroxyl groups respectively. For ехаmрlе,
Ethyl alcohol
(Monohydric)
1,2-Ethanediol
(Dihydric)
1,2,3-propanetriol
(Trihydric)
I.
Тhe alkyl alcohol system. In this system of common
nomenclature, the name of an alcohol is derived by
combining the name of the alkyl group with the word
alcohol. The names are mitten as two words.
n-butyl alcohol
isobutyl alcohol
tret-butyl alcohol
II. In this common system, the position of an additional
substituent is indicated by use of the Greek alphabet
rather than by numbers.
-chloroethyl alcohol
-bromobutyl alcohol
Any simple radical that has а common name may be used in
the alkyl alcohol system, with one important exception. The
grouping С6Н5 - has the special name phenyl, but the
compound C6H5OH is phenol, not phenyl alcohol.
phenol
Substituted phenols are named as derivatives of the parent compound
phenol. The reason for this difference is historical and arose from the fact
that phenol and its derivatives have many chemical properties that are
very different from those of alkyl alcohols. However, phenyl substituted
alkyl alcohols are normal alcohols and often have common names.
Examples are:
phenylmethanol
(benzyl alcohol)
2-phenylethanol
(-phenylethyl alcohol)
III. The carbinol system. In this system, the simplest alcohol,
СН3ОН, is called carbinol. More complex alcohols are
named as alkyl substituted carbinols. The names are written
as one word.
butylmethylcarbinol
triethylcarbinol
phenilcarbinol
The number of carbons attached to the carbinol carbon
distinguishes primary, secondary, and tertiary carbinols. As
in the case of the alkyl halides, this classification is useful
because the different types of alcohols show important
differences in reactivity under given conditions. The carbinol
system of nomenclature has been falling into disuse in recent
years. However, it is found extensively in the older organic
chemical literature.
Polyhydroxy alcohols: An alcohol in which two
hydroxyl groups are present is named as а diol, one
containing three hydroxyl groups is named as а triol,
and so on. In these names for diols, triols, and so
forth, the final –е of the parent alkane name is
retained for pronunciation reasons.
1,2-Ethanediol
1,2-propanediol
1,2,3-propanetriol
Classification of monohydric alcohols
Monohydroxy alcohols are hydrocarbon derivatives which
contain only one group –OH connected with sp³hybridizated carbon atom.
The general formula of monohydroxy alcohols is:
The names of monohydroxy alcohols are the names of the
same hydrocarbons with added prefix –ol.
Classification of monohydric alcohols. As already
mentioned, alcohols containing one ОН group per molecule
are called monohydric alcohols. These are further classified
as primary (1'), secondary (2'), and tertiary (3') according as
the ОН group is attached to primary, secondary and tertiary
carbon atoms respectively. For example:
Ethanol
Primary alcohol
Isopropyl alcohol
Secondary alcohol
2-Methylpropanane-2-ol
Tertiary alcohol
Isomery of monohydroxyl alcohols
Monohydroxyl alcohols are characterized by structural,
geometrical and optical isomery. Structural isomery depends
on different structure of carbon chain and different locations
of –OH group.
H 3C
CH2
CH2
CH2
OH
butanol-1
For unsaturated monohydroxyl alcohols structural isomery
depends on different locations of double bond too.
H 2C
CH
CH2 CH2 OH
butene-3-ol-1
H3C
CH
CH
CH2
butene-2-ol-1
OH
Only unsaturated monohydroxyl alcohols are
characterized by geometrical isomery.
H3C
CH2
C
OH
H
C
H
CH2
C
H
cys-butene-2-ol-1
OH
C
H 3C
H
trans-butene-2-ol-1
Optical isomery is characteristic for alcohols
which have asymmetric carbon atom in their
structure.
CH2
HO
*C
CH3
H
CH3
R-butanol-2
CH2
H
H3C
CH3
*C
OH
S-butanol-2
The methods of extraction of monohydroxyl alcohols
Alcohols can be obtained from many other classes
of compounds. Preparations from alkyl halides
and from hydrocarbons will be discussed in this
section. The following important ways of prераring
alcohols will be discussed later, as reactions of the
appropriate functional groups.
1. Hydrolysis of halogenderivatives of hydrocarbons
by heating:
CH3−CH2−Cl + NaOH → CH3−CH2−OH +
NaCl
2. Hydrogenation of alkenes. This reaction runs by
Markovnikov rule.
OH
H3C
CH
CH2 + H2O
H3C
CH
CH3
3. Reduction of carbonyl compounds (aldehydes, ketones,
carboxylic acids, complex ethers):
O
H3C
C
H
O
H3C
[H], Ni
C
Li+AlH4-
OH
O
H3C
[H]
C
O
C2H5
H3C
C
H3C
H3C
O
[H], Pt
H3C
CH2
OH
CH2 OH
H3C
CH2 OH
H3C
CH
H3C
OH
1. Alcohols have weak acidic and weak alkaline
properties. They can react with alkaline metals
like acids and form alkoxides:
2CH3CH2OH + 2Na → 2CH3CH2ONa + H2↑
2CH3CH2ONa + H2O ↔ CH3CH2OH + NaOH
2. Alcohols can react with mineral and organic acids
(complex ethers form) like alkalis:
CH3CH2OH + HONO2 ↔ CH3CH2ONO2 + HOH
O
O
H 3C
CH2
C
O
H +
CH3
H 3C
HO
C
O
CH2
+ H 2O
CH3
3. Dehydration of alcohols. There are 2 types of dehydration:
a) Dehydration between 2 molecules:
H3C
CH2
O
H +
HO
CH2
CH3
H3C
CH2
O
CH2
CH3
b) Dehydration in the molecule (intramolecular dehydration):
H
H
H
C
C
H
OH
H
CH2
CH2 + H2O
4. Reaction with HI, HCl, HBr:
CH3CH2OH + HI → CH3CH2I + H2O
5. Oxidation
H3C
CH2
OH
[O]
-H2O
O
H3C
C
H
[O]
O
H3C
C
OH
Primary alcohol aldehyde = carboxylic acid
Secondary alcohol = ketone
Tertiary alcohol = no reaction
The general reaction for the oxidation of а primary
alcohol is
Alcohol
Aldehyde
Carboxylic acid
In this equation, the symbol [O] represents the mild oxidizing agent. The
immediate product of the oxidation of а primary alcohol is an aldehyde.
Because aldehydes themselves are readily oxidized by the same
oxidizing agents that oxidize alcohols, aldehydes are further converted to
carboxylic acids. А specific example of а primary alcohol oxidation
reaction is
The three classes of alcohols behave differently toward mild
oxidizing agents. The general reaction for the oxidation of а
secondary alcohol is
Alcohol
Ketone
As with primary alcohols, oxidation involves the removal of two
hydrogen atoms. Unlike aldehydes, ketones are resistant to
further oxidation. А specific example of the oxidation of а
secondary alcohol is
Tertiary alcohols do not undergo oxidation with mild
oxidizing agents. This is because they do not have
hydrogen on the -ОН-bearing carbon atom.
CH3
C
OH
H
To determine any alcohol (which contain fragment
in
the mixture of compounds it is needed to use iodoform test.
As the result yellow precipitate forms.
CH3
R
C
I
OH
NaOI or NaOH+I2
O
I
C
I+
R
H
H
iodoform
(yellow
precipitate)
C
O Na
+
Di-, tri- and polyhydroxyl alcohols
Dihydroxyl alcohols contain two groups –OH in the molecule.
They are called diols. There are several types of diols.
1. α-diols (groups –OH are situated near neighboring carbon
atoms in 1,2-locations);
2. β-diols (groups –OH are situated in 1,3-locations);
3. γ-diols (groups –OH are situated in 1,4-locations) etc.
R
CH
CH
OH
OH
R1
R
CH
CH2 CH
OH
OH
2
1
R
CH
CH2
OH
CH2
CH
OH
3
R1
R1
Trihydroxyl alcohols contain three groups –
OH in the molecule. They are called triols.
The representative is glycerin:
CH2 CH
OH
OH
CH2
OH
.
To extract glycerin it is necessary to use next reaction:
CH2
Cl
KOH
CH
Cl +
CH2
Cl
CH2
OH
KOH
CH
OH + 3KCl
KOH
CH2
OH
b) Chemical properties of di-, tri- and polihydroxyl alcohols
1. Reaction with alkaline metals
2
2
CH2
OH
+ 2Na
CH2
OH
CH2
ONa
+ 2Na
CH2
OH
2
2
CH2
ONa
+ H2
CH2
OH
CH2
ONa
CH2
ONa
+ H2
2. Reaction with Cu(OH)2
CH2
OH
2
CH2
H
OH
+ Cu(OH)2
H2C
H2C
O
O
Cu
O
O
H
blue colour
CH2
CH2
+ 2H2O
3. Reaction with HI, HCl, HBr:
CH2
OH
CH2
+ HCl
CH2
4.
Cl
+ H2O
OH
CH2 OH
Formation of simple and complex ethers (reaction with
monohydroxy alcohols and organic acids):
CH2 OH
CH2 OH
+
HO
H 2C
CH2
CH3
CH2
O
CH2
CH3
+ H 2O
OH
incomplete simple ether
1
CH2
CH2
O
OH
CH2
CH3
CH2
+ HO
H 2C
CH3
CH2
O
O
CH2
CH2
CH3
CH3
complete simple ether
+ H2O
O
O
CH2 OH
CH2 OH
+ HO
C
CH2
CH3
CH2
O
C
CH3
+ H2O
OH
incomplete complex ether
2
O
O
CH2
CH2
O
C
O
CH3
+ HO
OH
CH2
C
CH3
O
CH2
O
C
C
CH3
CH3
O
complete complex ether
5. Reaction with mineral acids:
CH2
OH
CH2
OH
CH2
O
CH2
OH
+ HONO2
NO2
+ HONO2
CH2
CH2
O
NO2
+ H2O
OH
CH2
CH2
O
O
NO2
NO2
+ H2O
+ H2O
6. Oxidation by KMnO4
O
CH2
OH
CH2
OH
[O]
C
OH
C
OH
O
7. Dehydration
OH
HO
H2C
O
CH2
+
H2C
CH2
OH
HO
H2SO4, t H2C
CH2
H2C
CH2
+ 2H2O
O
dioxane
CH2
OH
CH2
CH2
CH2 H SO , t H2C
2
4
OH
CH2
H2C
CH2
O
+ H2O
8. Polycondensation
HO H2C CH2 OH + HO H2C CH2 OH
H2SO4
HO H2C CH2 O H2C CH2 OH
9. Diols react intramolecularly to form cyclic ethers when a fivemembered or sixmembered ring can result.
Thioalcohols
Thioalcohols are compounds which contain aliphatic
(CnH2n+1) and mercaptane (−SH) groups. Thiols are given
substitutive IUPAC names by appending the suffix -thiol to
the name of the corresponding alkane, numbering the chain
in the direction that gives the lower locant to the carbon that
bears the −SH group.
The preparation of thiols involves nucleophilic substitution of
the SN2 type on alkylhalides and uses the reagent thiourea
as the source of sulfur.
Both steps can be carried out sequentially without isolating
the isothiouronium salt.
1.
Chemical properties of thiols:
Thiols can react with ions of alkaline and heavy metals (this
property of thiols is used in medicine at the poisoning by
heavy metals):
C2H5SH + NaOH → C2H5S−Na+ + H2O
2C2H5SH + Hg²+ → (C2H5S)2Hg + 2H+
2. They can react with alkenes (peroxides are catalysts):
H3C
S
H + H2C
CH
CH3
H3C
S
CH2 CH2 CH3
3. Reaction with organic acids:
O
C2H5 SH + H3C
C
O
H3C
OH
C
+ H2O
S
C2H5
4. Oxidation
C2H5 S
H + [O] + H
S
CH3
C2H5 S
S
CH3 + H2O
To prepere thioalcohols it is
necessary to use next reactions:
1.
C2H5Cl + NaSH → C2H5SH + NaCl
2. C2H5OH + Na2S → C2H5SH + H2O
Ethers (simple ethers)
The general formula of simple ethers is:
R−O−R1
The radicals can be similar or different.
Ethers are named, in substitutive IUPAC nomenclature, as
alkoxy derivatives of alkanes. Functional class IUPAC names
of ethers are derived by listing the two alkyl groups in the
general structure ROR1 in alphabetical order as separate
words, and then adding the word “ether” at the end. When
both alkyl groups are the same, the prefix di- precedes the
name of the alkyl group.
Physical properties of ethers
It is instructive to compare the physical properties of ethers
with alkanes and alcohols. With respect to boiling point, ethers
resemble alkanes more than alcohols. With respect to
solubility in water the reverse is true; ethers resemble alcohols
more than alkanes.
In general, the boiling points of alcohols are unusually high
because of hydrogen bonding. Attractive forces in the liquid
phases of ethers and alkanes, which lack - OH groups and
cannot form intermolecular hydrogen bonds, are much
weaker, and their boiling points lower. These attractive forces
cause ethers to dissolve in water to approximately the same
extent as comparably constituted alcohols. Alkanes cannot
engage in hydrogen bonding to water.
The methods of extraction of ethers:
1. From alkoxides:
CH3CH2ONa + CH3I → CH3CH2OCH3 + NaI
2. Dehydration of alcohols (dehydration between 2
molecules):
H3C CH2 O
H +
HO CH2 CH3
H3C CH2 O CH2 CH3
Chemical properties of ethers
1.
Reaction with concentrated mineral acids (formation of
oxonium salts):
+
H3C
CH2
O
CH3 + HONO2
H3C
CH2
O
CH3
NO3
H
2.
A second dangerous property of ethers is the ease with
which they undergo oxidation in air to form explosive
peroxides. Air oxidation of diethyl ether proceeds
according to the equation
The reaction follows a free-radical mechanism and gives a
hydroperoxide, a compound of the type ROOH.
Hydroperoxides tend to be unstable and shock-sensitive. On
standing, they form related peroxidic derivatives, which are
also prone to violent decomposition. Air oxidation leads to
peroxides within a few days if ethers are even briefly
exposed to atmospheric oxygen. For this reason, one should
never use old bottles of dialkyl ethers, and extreme care
must be exercised in their disposal.
3. Reaction with HI
CH3−O−CH3 + HI → CH3−OH + CH3I
The mechanism for the cleavage of ethers by hydrogen halides,
using the reaction of diethyl ether with hydrogen bromide as
an example.
Step 1: Proton transfer to the oxygen of the ether to give a
dialkyloxonium ion.
Step 2: Nucleophilic attack of the halide anion on carbon of
the dialkyloxonium ion. This step gives one molecule of
an alkyl halide and one molecule of an alcohol.
Step 3 and Step 4: These two steps do not involve an ether
at all. They correspond to those in which
an alcohol is converted to an alkyl halide .
11. Enols
Enols (also known as alkenols) are alkenes with a hydroxyl group affixed to
one of the carbon atoms composing the double bond. Enols and carbonyl
compounds (such as ketones and aldehydes) are in fact isomers; this is
called keto-enol tautomerism:
The enol form is shown above on the left. It is usually
unstable, does not survive long, and changes into the keto
(ketone) form shown on the right. This is because oxygen is
more electronegative than carbon and thus forms stronger
multiple bonds. Hence, a carbon-oxygen (carbonyl) double
bond is more than twice as strong as a carbon-oxygen single
bond, but a carbon-carbon double bond is weaker than two
carbon-carbon single bonds.
The name of enols systematic nomenclature IUPAC
form the name alkene to which is added the suffix-ol:
CH2=CH-OH
CH2=CH-CH2-OH
ethenol, vinyl alcohol
Propenol-1(unsaturated alcohol)
Hydration of acetylene as the intermediate substance
is formed vinyl alcohol (enol), which isomerization in
acetic aldehyde.
H2O,Hg²+,H+
C2H2
CH2=CH-OH
This property of enols characterizes the rule of
Eltekov-Erlenmeyer. - Compounds in which the
hydroxyl group located at carbon atoms that
forms a fold communication, unstable and
isomerization of carbonyl compounds - aldehydes
and ketones
Aminoalcohols
Amino alcohols are organic compounds that
contain both an amine functional group and
an alcohol functional group.
NH2-CH2-CH2-OH
N(C2H5)-CH2-CH2OH
2-aminoethanol
2-N,N- diethylaminoethanol
If the molecule of amino alcohol contains the in its
composition two or three hydroxyalkylnes groups,
through the combination of nitrogen atom, in this
case, the basis takes the name amine.
OH-CH2-CH2-NH-CH2-CH2-OH
di (β-oxyethyl) amine, or di (2-hydroxyethyl) amine
The methods of extraction of aminoalcohols
1. Accession of ammonia or amines to the α-oxyses.
CH2-CH2 + NH3
NH2-CH2-CH2-OH
O
2. Reduction of nithroarenes.
CH3-CH(NO2)-CH2-OH + 3H2
CH3-CH(NH3)-CH2-OH + 2H2O
Chemical properties of aminoalcohols
Aminoalcohols show properties as alcohols and
amines. As a basis aminoalcohols form salts with
mineral acids.
OH-CH2-CH2-NH2 + HCl
OH-CH2-CH2-NH3Cl¯
The nomenclature and isomery of mononuclear phenols
Numbering of the ring begins at the hydroxylsubstituted carbon and proceeds in the direction that
gives the lower number to the next substituted carbon.
Substituents are cited in alphabetical order.
HO
N
H
C CH3
C2H5O
C2H5O
C CH3
O
O
Paracetamol, (N-acetyl-p-aminophenol
p-hydroxyacethanilide),
N
H
Phenacetin (p-еthoxyacethanilide)
NH2
Phenetidine (p-ethoxyaniline)
The structural isomery of phenols is obtained by
different locations of radicals and structural changes
of radicals.
H3C H2C H2C
4-propylphenol
OH
H3C
HC
OH
H3C
4-isopropylphenol
The methods of extraction of monohydric phenols
1.Natural sources (from coal tar)
C 6 H 5 -OH + NaOH
C 6 H 5 -ONa + H
Phenolyath
2O
sodium
С6H5-ONa + H2O + CO2
C6H5-OH + NaHCO3
2. The synthesis from arenes
SO 3 H
OH
4NaOH
SO 3 H
4000 C
+ 2Na2 SO3 + 2H2 O
OH
3. Cumol (isopropyl toluene) synthesis
C 6H 5
H 3C
C
C 6H 5
H
O 2 (OH-)
H 3C
1300 C
C
CH 3
..
O
..
..
O
..
H+
H
H 3C
Acetone
4. The extraction from diazonium salts
_
+
OH
HOH
+ N2 + HCl
R
R
5. The substitution of halogen atom to –OH group
NH2. HCl
OH
3HOH
HCl . H2 N
NH2 . HCl
+ 3NH4 Cl
HO
Cl
OH
OH
NO 2
NO 2
NaOH, H2 O
-HCl
NO 2
+ C 6 H5 OH
O
Cumol
N Cl
CH 3
650 C
CH 3
+
N
C
NO 2
Phenol
Physical properties of phenols

Substance

..
O
..


H
H3 C
CH2

..
O
H
..
lС-О, nm
0,140
0,144
, D
1,53
1,66
, сm-1
1230
1050-1200
 < 
18. Chemical properties of mononuclear phenols
1. Acidic properties:
C6H5−OH + NaOH ↔ C6H5−ONa + H2O
C6H5−ONa + H2O ↔ C6H5−OH + NaOH
OH
NO
O N
H3C
O
H
2
NO
2
2
Picric acid
O
N
-O
O
+
O
N
H
-O
O + H+
2. Forming of simple and complex ethers:
C6H5−ONa + C2H5−Br ↔ C6H5−O−C2H5 + NaBr
ethylphenyl ether
C6H5−ONa + CH3−COCl ↔ C6H5−O−CO−CH3 + NaCl
phenylacetate
3. Halogenations. (The reaction that underlies qualitative and quantitative
analysis of phenol and its derivatives)
OH
OH
Br
Br
+ 3Br2
O
Br
Br
+Br2
-3Br2
-HBr
Br
Br
Br
white precipitate
yellow precipitate
4. Nitrating
OH
OH
OH
NO2
HNO3 (H2O)
+
t=25
2
+ 2H2O
o-nitrophenol
NO2
p-nitrophenol
5. Sulphating
OH
OH
OH
H2SO4
t=-20
SO3H
o-hydroxybenzylsulphoacid
H2SO4
t=+100
HO3S
p-hydroxybenzylsulphoacid
6. Alkylation and acylation (the catalysts are H2SO4, H3PO4,
BF3:
OH
OH
OH
CH3
2
+ 2 H3C
OH
+ 2H2O
+
CH3
OH
OH
O
2
+ 2 H3C
C
OH
O
C
CH3
+ 2H2O
+
OH
O
C
CH3
7. Azoaccession
+
N
NaOH
_
N Cl
OH
+
-NaCl, -H2O
R
N N
OH
R
8. The synthesis of phenolocarboxylic acids:
_
O Na
+
OH
OH
O
+
C
COONa
125 0C, p
COOH
HCl
-NaCl
O
salicylic acid
sodium salicylate
9. To determine mono-, di-, tri- and polynuclear phenols it is necessary to do
the reaction with FeCl3. As the result of this reaction color complex
H
OC6 H5
H
compounds form.
C6 H5
6C6H5OH + FeCl3
O:
:O
C6 H5
Fe
-3HCl
C6H5
O
..
O
H
O
C6 H5
C6 H5
The coloration of phenols in reaction with FeCl3
Name of phenol
Color products of
reaction with FeCl3
pyrocatechol
green color
resorcinol
blue color
hydroquinone
pyrogallol
green color that turns to
yellow color
red color
phloroglucinol
dark violet color
Oxidation of phenols. Quinones.
Phenols are more easily oxidized than alcohols, and a large
number of inorganic oxidizing agents have been used for this
purpose. The phenol oxidations that are of the most use to the
organic chemist are those involving derivatives of 1,2benzenediol (pyrocatechol) and 1,4-benzenediol
(hydroquinone). Oxidation of compounds of this type with
silver oxide or with chromic acid yields conjugated dicarbonyl
compounds called quinones.
19. Usage of the chemical properties in the receiving of
medical drugs
А) Synthesis of thymol:
CH 3
CH 3
H 2SO 4
HSO 3
(CH 3) 2CHOH
OH
CH 3
HSO 3
OH
H 3C
CH 3
H2O
OH
H 3C
OH
CH 3
thymol
CH 3
B) Synthesis of paracetamol (pyretic and analgesic means):
NO 2 2H
2
NH-OH H 2SO 4
NH 2 (CH CO) O
3
2
HO
NHCOCH 3
HO
p-acetylaminophenol,
paracetamol
C) Synthesis of phenethidine and phenacetine (pyretic and
anti-neuralgic means)
C 2H 5Br
NaOH
HO
NH 2
NaO
NH 2
-NaBr
C 2H 5O
NH 2
phenethidine
(CH 3CO) 2O
C 2H 5O
NHCOCH 3
phenacetine
20. Di-, tri- and polynuclear phenols
OH
OH
OH
OH
naphthol
anaphthol
pyrocatechol
O H
O H
O H
O H
H O
pyrogallol
OH
hydroquinone
O H
H O
OH
O H
O H
phloroglucinol
hydroxyhydroquinone
21. Chemical properties of di-, tri- and polynuclear
phenols
Chemical properties of di-, tri- and polynuclear phenols are
similar to chemical properties of mononuclear phenols. But
they have some peculiarities.
1. Acidic properties of polynuclear phenols are stronger than
acidic properties of mononuclear phenols. Polynuclear
phenols can react with alkaline and heavy metals:
O
OH
(CH3COO)2Pb
Pb
-2CH3COOH
OH
O
2. Oxidation. polynuclear phenols oxidize more easily
than mononuclear phenols.
O
OH
Ag2O, ether
Na2SO4
OH
pyrocatechol
O
o-benzoquinone
22. The representatives of phenols
OH
phenol. Colourless crystals, it has antiseptic properties.
It is toxic and can cause combustions. It is used in the
manufacture of dyes, medicines.
OH
CH3
o-, m- and p-cresols. They are
disinfectant compounds and used in
veterinary medicine.
OH
H3C
CH
CH3
thymol. Colourless crystals. It is used in
medicine as antiseptic and antihelminthic mean.
CH3
OH
NO2
O2N
picric acid. Yellow crystals. It is used in
pharmaceutical analysis.
NO2
OH
α-naphtol. Yellowish crystals. It is used in the
manufacture of dyes, medicines.
OH
OH
O
pyrocatechol. Colourless
crystals. It can oxidize to
(CH3COO)2Pb
brown colour in the open
Pb air. It has antiseptic properties.
-2CH3COOH
It take part in the synthesis of adrenalin.
OH
HO
β-naftol. White powder. It is used in the manufacture of
dyes, medicines and in pharmaceutical analysis.
OH
O
resorcinol. Colourless crystals. It is used in the
manufacture of dyes. It is antiseptic compound by skin
diseases (the ointments contain it).
OH
HO
pyrogallol. White crystals. It can oxidize to brown
colour in the light. It is used in the manufacture of
dyes.
OH
HO
OH
phloroglucinol . Colourless crystals. It is used in
pharmaceutical analysis.
OH
HO
CH
OH
HO
CH2
NH
CH3
adrenalin. Colourless crystals. It is a hormone of
catecholamines, it is produced by inner cerebral
part of paranephroses. Adrenalin takes part in
regulation of carbohydrate metabolism and
lipometabolism. It causes narrowing of little blood
vasculars, rising of arterial pressure, it can stimulate
of heart activity.
23. Aminophenols
Aminophenols are aromatic compounds that
contain phenyl radical, −OH group and
aminogroup. There are o-, m- and paminophenols.
OH
OH
OH
NH2
NH2
o-aminophenol
m-aminophenol
NH2
p-aminophenol
The methods of extraction of aminophenols
1.
The reduction of nitrophenols:
OH
OH
NH2
NO2
3H2
o-aminophenol
o-nitrophenol
2.
+ 2H2O
Reaction of dihydroxic phenols with ammonium:
OH
OH
t
+ NH3
+ H2O
OH
NH2
pyrocatechol
o-aminophenol
3.
The reduction of nitrobenzene:
NO2
N
H2
NH
nitrozobenzene
NH2
OH
H2SO4
H2
-H2O
nitrobenzene
O
HO
phenylhydroxylamine
p-aminophenol
Chemical properties: aminophenols have properties of
phenols and aromatic amines.
The derivatives of aminophenols are medical
preparations:
It is antipyretic, antiinflammatory mean. It is
used for the treatment of
headache, toothache, high
temperature.
O
HO
NH
C
CH3
p-acetylaminophenol
(paracetamol)
O
H3C
H2C
O
NH
C
CH3
phenacetin
It is antipyretic and antineuralgic mean
24. Aromatic carboxylic acids
Aromatic carboxylic acids are the derivatives of hydrocarbons
that contain carboxyl group (-COOH) and benzyl radical.
O
O
H2C
H3C
C
C
OH
OH
3-ethylbenzoic acid
H 3C
HNO 3
benzoic acid
H 3C
NO 2
C 2H 5OH, H2SO 4
[O]
O 2N
COOH
[H]
O 2N
COOCH 5
2
H 2N
COOCH
2 5
anesthysine
COONa
COOH
OH
NH 2
Anthranilic acid
NH2
Sodium p-aminosalicylate
H 2N
COOCH 2CH 2N(C 2H 5) 2 . HCl
novocaine
The key compound in the synthesis of aspirin,
salicylic acid, is prepared from phenol by a process
discovered in the nineteenth century by the German
chemist Hermann Kolbe. In the Kolbe synthesis, also
known as the Kolbe–Schmitt reaction, sodium
phenoxide is heated with carbon dioxide under
pressure, and the reaction mixture is subsequently
acidified to yield salicylic acid:
OH
C
COONa POCl 3, C 6H 5ONa
NaHCO 3
O
OH
OC 6H 5
-CO 2, -H 2O
-NaCl, -NaPO 3
Phenylsalicylate, salol
Sodium salicylate
O
OH
COOH
O
(CH 3CO) 2O
C
NH 2
CH 3
COOH
-C 6H 5OH
- CH 3COOH
Salicylic acid
Acetylsalicylic acid,
aspirin
CH 3OH
-H 2O
OH
(H 2SO 4)
OH
OH
COOCH 3
Methylsalicylate
O
OH
C
NH 3
O
C
NH 2
NH
Salicylamide
Oxaphenamide
OH
Salicylic acid (from the Latin word for the willow tree, Salix, from whose
bark it can be obtained) is a beta hydroxy acid. This colorless crystalline
organic acid is widely used in organic synthesis and functions as a plant
hormone. It is derived from the metabolism of salicin. In addition to being
a compound that is chemically similar to but not identical to the active
component of aspirin (acetylsalicylic acid), it is probably best known for
its use in anti-acne treatments. The salts and esters of salicylic acid are
known as salicylates.
4-Aminosalicylic acid, commonly known as PAS, is an
antibiotic used to treatment of tuberculosis.
COOH
OH
OH
OH
CO2 , KOH
NH3
-H2 O
OH
NH 2
NH 2
PAS
The best known aryl ester is O-acetylsalicylic acid, better
known as aspirin. It is prepared by acetylation of the
phenolic hydroxyl group of salicylic acid:
Aspirin possesses a number of properties that make it an
often-recommended drug. It is an analgesic, effective in
relieving headache pain. It is also an antiinflammatory
agent, providing some relief from the swelling associated
with arthritis and minor injuries. Aspirin is an antipyretic
compound; that is, it reduces fever. Each year, more
than 40 million lb of aspirin is produced in the United
States, a rate equal to 300 tablets per year for every
man, woman, and child.
Thank you for attention!