Python Notes for mca i year students osmania university.docx
Alcohol chemistry
1.
2. When you know chemistry, there’s a new
level of looking at the world around you.
3. The voltage needed to create an electron is about one million
volts. This is the voltage that creates a bolt of lightning. This
voltage pushes electrons from the sky to the ground, but the
electrons are slowed down by the air. If they weren’t, it would
be possible that two electrons accelerated by a million volts
striking the ground would give off light of enough energy to
create a new electron.
4. Alcohol Chemistry
Alcohols are derivatives of hydrocarbons in which an –OH
group has replaced a hydrogen atom.
Alcohols have one or more hydroxyl (–OH)
functional groups
A family of compounds with the same general
formula, similar chemical properties and a graduation
in physical properties.
C5H11OH pentanol
C4H9OH butanol
C3H7OH propanol
C2H5OH ethanol
CH3OH methanol
C6H13OH hexanol
5
4
3
2
1
NameNo. of
carbon atoms
Molecular
formula
6
5. Chemistry
changes
the way
you look at
the world.
I found te
picture of
the eyes
but added
various
autoshape
objects.
They were
rotated
with the
Spin
Emphasis
effect,
which was
set to
repeat
using the
“Effect
Option”
menu.
6. Structure of alcohol
Hydroxyl (OH) functional group
Oxygen is sp3 hybridized
O – H bond is polar
Classification of alcohol – monohydroxy derivative
Primary: carbon with –OH is bonded to one other carbon.
Secondary: carbon with –OH is bonded to two other carbons.
Tertiary: carbon with –OH is bonded to three other carbons.
Aromatic (phenol): -OH is bonded to a benzene ring.
OH
RH
H
OH
HH
H
OH
RH
R
OH
RR
R
Methanol 10
alcohol 20
alcohol 30
alcohol
CH3 CH
CH3
CH2OH
CH3 CH
OH
CH2CH3
CH3 C
CH3
CH3
OH
OH
7. Here I do two effects on
the text at the same time.
For example, I’m using
motion paths with either
a fade in zoom or a fade
out. On the original
slide, I followed this
animation with a movie
clip from the Matrix.
If you choose
to stay in this
class…
8. IUPAC Nomenclature – general rules
Identify the parent chain: Longest chain having –OH group – Replace letter ‘e’
of parent alkane by letter ‘ol’ with the appropriate position number
before the name.
Number the parent chain: Carbon having –OH group should have lowest
number.
Name the substituents and place them alphabetically in front of the parent
chain.
Assign stereochemistry (stereocenters present in molecule).
OH
H
H
3-methylbutan-1-ol
OH
H
OH
(S)-4-methylpentan-2-ol 2-methyl-4-phenylbutan-2-ol
1234
5
1
1
2
2
3
3
4
4
9. IUPAC Nomenclature – Polyhydroxy compounds
When there is more than one OH group, the name must specify the total number
and positions of the functional groups.
An alcohol with two OH groups is a diol, one with three OH groups is a triol, and
so on. Note that the ‘e’ on the end of the alkane root name is retained
12
4
OH
OH
1
23 OH
propane-1,2,3-triol
HO OH
ethane-1,2-diol
HO OH
ethane-1,2-diol
1
2
OH
OH
1
23 OH
HO
butane-1,2,3,4-tetraol
HO
OH
OH
OH
OH
OH
hexane-1,2,3,4,5,6-hexaol
(sorbitol)
10. IUPAC Nomenclature – cyclic alcohols
The ring is the parent chain, give number to the ring so as the hydroxyl group
carbon of the ring has lowest number.
The name of parent alcohol is cycloalkanol.
Arrange the substituents alphabetically before the name of parent alcohol
with number where they are attached.
OH
OH
OH
OH
OH
OH
cyclopropanol cyclobutanol cyclopentanol cyclohexanol
3-methylcyclohexanol3-methylcyclopentanol
When two OH groups or substituents are present and are attached to different C
atoms in the saturated ring, stereoisomers are possible then specify their
stereochemistry with number before the name of parent alcohol.
OH
HO
HO
OH
HO
OH
OH
HO
trans-cyclohexane-1,4-diolcis-cyclohexane-1,4-diol
11. Naming Alcohols CH3CHCHCH3
OH
CH3
3-methyl-2-butanol
1. Name the parent compound – 4 carbons = butane
2. Replace the –e with –ol = butanol
3. Number the parent chain to minimize number of carbon with the –OH
group = number from right to left
4. Identify, name, and number all substituents = methyl on C-3
OH
CH3
3-methylcyclohexanolOH must be at C-1
1. Name the parent compound – 6 carbon ring = cyclohexane
2. Replace the –e with –ol = cyclohexanol
3. Number the ring to minimize number of carbon with the –OH group =
number counter-clockwise.
4. Identify, name, and number all substituents = methyl on C-3
12.
13. • R-O-H has a structure similar to that of water,
• Hydroxyl group is very polar,
• Hydrogen bonds can form readily.
Physical Properties of alcohols
Pure form
Aq. solution
14. Alcohols have abnormally high boiling
points relative to their molecular
weights due to their ability to hydrogen
bond. CH3
CH2
OH
CH3O CH3
CH3CH2CH3
bp -42 oC
bp -23 oC
bp +78.5 oC
Physical Properties of alcohols
Low molecular weight alcohols (up to 5-6
carbons) are soluble in water –
Because of polar nature of –OH group
CH3CH2OH very soluble
CH3OCH3 barely soluble
CH3CH2CH2CH2OH, 7 g per 100 mL
HOCH2CH2CH2CH2OH is very soluble
Solubility decreases as the size of the alkyl group increases -
Ratio of hydroxyl
groups to carbons in
the chain determines
solubility
16. Acidic and basic properties of alcohol
Alcohols can act both so donate a proton (acts as a Brønsted acid) and accept a proton (acts
as Brønsted base). Aliphatic alcohols act as weak acids and bases.
pKa of alcohol is 13 - 16
O
H + H+ O
H
H
Protonation of alcohols by mineral acids is analogous to the formation of the oxonium
ion which is important for nucleophilic substitution reaction in which it converts –OH into
the molecule with a good leaving group (i.e. H2O)
17. R1
OHR2
R3
R1
HR2
R3
H
2Ocat.concH
2SO
4
R1
HH
H
R2 = R3 = H
Hg(OAc)2H2O
R1
HH
H
H HgOAc
R1
HR2
R3
B2H6
R1
HR2
R3
H B
H2O2/HO-
R1
H
R2
R3
X
HO
-
R1
R2
R3
O
R1 -H - aldehyde
H2/Pt, Pd, Ni, Ru
R1
R2
R3
O
ketone
R1
R2
R3
O
R1 -H - aldehyde
R1
R2
R3
O
ketone
R1
R2
R3
O
acid or its derivative
R1 - OH, OR, X, NR2, etc
or LiAlH4
NaBH4
MgBr
R2
R3
R4
R1
O
H
R4 -H - aldehyde
R4
R1
O
ketone
R
R1
O
acid or its derivative
R - OH, OR, X,
NR2, etc; R4 - H
1. 2.H3O+
Reduction
Reduction
Reduction
Hydration
Nucleophilic
Substitution
By using Grignard reagent
Epoxide
Synthesis/Preparations
of alcohols
18. From alkene – Hydration (acid catalyzed)
Reversible reaction
From alkene – Hydration (by using mercury(II) acetate)
Addition of water to the carbon-carbon double bond of an alkene produces an alcohol
19. From alkene – Hydration (by using borane in presence of alkaline peroxide)
23. Synthesis of alcohol - Using Grignard reagent
H
OHR2
R3
MgBrR2
R3
H
H
O
H
Formaldehyde
R4
R1
O
ketone
R
R1
O
acid or its derivative
R - OH, OR, X, NR2, etc; R4 - H
1.
2.H3O+
R1
O
H
Aldehyde
MgBr
R2
R3
1.
2.H3O+
10
- alcohol
R1
OHR2
R3
H 20
- alcohol
MgBr
R2
R3
1.
2.H3O+
R1
OHR2
R3
R4 30
- alcohol
MgBr
R2
R3
1.
2.H3O+
R1
O
R2
R3
30
- alcohol
Synthesis by
using Grignard
Reagent
O
Epoxide R2
R3 OHMgBr
R2
R3
1.
2.H3O+
10
- alcohol
24. Reactions
of alcohols R
OH
HX
R
O
H
H R
X
Substitution - SN1 / SN2
HCl/ZnCl2
X = Br, I
Lucas Test - Zn2+
lewis acidR
Cl
H2SO4
R
O
H
H
H
R
-H2O
Dehydration
Elimination - E1 / E2
H2SO4 R
O
H
H
H
R OH R
O
H
R
-H2O
Williamson
synthesis
POCl3
py
R
O
H
P
H
O
Cl
Cl
R
Dehydration
2 Na
R
ONa
H
R1X R
O
H
R1
PBr3
SOCl2
R
O
H
P
H
Br
Br
Br-
R
Br
Synthesis of ether
R
O
H
S
H
O
Cl
Cl-
R
Cl
Synthesis of
alkyl halide
oxidation R
O
Reagent - Cu/heat, CrO3, H2CrO4,
Na2Cr2O7, KMnO4, PCC, PDC, COCl2,
HIO4, etc.aldehyde/ketone
R1COOH
R
O
C
H
O
R1
Ester synthesis
Alcohol
Reactions of
Alcohol
29. Dehydration - Williamson ether synthesis
R OH + 2 Na2 R O-
Na+
+ H2
O H3C I O
CH3
+
Computation between
elimination & substitution
Alcohols are converted into ethers by the formation of corresponding alkoxide ion
followed by the reaction with alkyl halide, a reaction is known as Williamson ether
synthesis.
32. Ester formation
The reaction between an alcohol and a carboxylic acid or acyl chloride produces an ester.
Reversible
An alternative method of preparing esters is the condensation reaction between an acyl
chloride and an alcohol in which HCl is eliminated. The librated HCl is neutralized by
weak base.
33. • What product would be formed from the reaction of the following?
a. 2-bromobutane and hydroxide ion
b. (R)-2-bromobutane and hydroxide ion
c. (S)-3-chlorohexane and hydroxide ion
d. 3-iodopentane and hydroxide ion
• Give the product formed from the reaction of each of the following alcohols with
a. an acidic solution of sodium dichromate:
b. by Swern oxidation of:
1. 3-pentanol 3. 2-methyl-2-pentanol 5. cyclohexanol
2. 1-pentanol 4. 2,4-hexanediol 6. 1,4-butanediol
34. Chemistry of Phenol
Phenols are compounds that have a hydroxyl group bonded directly to a benzene
or benzenoid ring i.e. on sp2 hybridized carbon atom.
The parent compound of this group, C6H5OH, called simply phenol.
OH
sp2
hybridized carbon
Aromatic ring
OH
OH
naphthalen-1-ol naphthalen-2-olphenol
35. Nomenclature of phenol derivatives
An old name for benzene was phene, and its hydroxyl derivative came to be called
phenol which acceptable name by IUPAC.
The names methyl phenols are also accepted by IUPAC, are known as o-, m-, and
p-cresol.
The common names for the two hydroxy derivatives of naphthalene are 1-
naphthol and 2-naphthol is also acceptable.
phenol
HO HO CH3
m-cresol
HO HO HO
HO
OH
OH
pyrocatechol resorcinol hydroquinone
1
2
3
4
5
6
1
2
3
4
5
6
1
2
3
4
5
6
(1,2-benzenediol) (1,3-benzenediol) (1,4-benzenediol)
OH
OH
naphthalen-1-ol
(1-Naphthol)
(-Naphthol)
naphthalen-2-ol
(1-Naphthol)
(-Naphthol)
36. For the compounds containing phenolic OH and carboxylic or acyl group, the
during predication of IUPAC nomenclature, Carboxyl and acyl groups are
consider as parent group and the phenolic hydroxyl is the substituent.
Numbering of the ring begins at the hydroxyl-substituted carbon and proceeds
in the direction that gives the lower number to the next substituted carbon.
Substituent's are cited in alphabetical order.
HO
Cl
HO Cl
A B
H3COC HOOC
OH
1
2
3
4
5
6
1
2
3
4
5
6
OH
1-(2-hydroxy-4-methylphenyl)ethanone 4-hydroxybenzoic acid
37. Resonance stabilization of phenoxide ion
Phenol is planar, with a C-O-H bond angle of 1090, which is almost the same as the
tetrahedral angle and not much different from the bond angle C-O-H (108.50) of
methanol.
The carbon–oxygen bond distance (136 pm) in phenol is slightly less than that in
methanol (142 pm). The shorter C-O bond length is observed due to the partial
double-bond character that results from conjugation of the unshared electron pair
of oxygen with the aromatic ring. This resonance is used to explain many
properties of phenol.
Some of them are listed here. The hydroxyl oxygen is less basic (less electron
density); the hydroxyl proton more acidic, in phenols than in alcohols;
Electrophiles attack the aromatic ring of phenols much faster than they attack
benzene.
O
phenol
H
O
H
O
H
O
H
O
H
Resonance structures of phenol(Stable)
(Stable)
38. Physical properties and acidic character
Because of acidic property of phenol, it was known as carbolic acid.
Phenols are more acidic than alcohols but less acidic than carboxylic acids.
The ionization constants pKa of carboxylic acids have of approximately 5; whereas
the pKa’s of alcohols are in the range of 16 to 20 and of phenol is 10.
The more acidic character of phenol than ethanol is explained by comparing the
ionization equilibria for phenol and ethanol.
phenol
H+
HO +
Na-
O
H3C
H2
C
O
H H3C
H2
C
O- + Ka = 10-16
(pKa = 16)
H++ Ka = 10-10
(pKa = 10)
ethanol ethoxide ion
phenoxide
39. 1. The negative charge in ethoxide ion is localized on oxygen and is stabilized only
by solvation forces but the negative charge in phenoxide ion is stabilized both by
solvation and by electron delocalization (resonance effect of pi-electron of ring)
into the ring.
2. The OH group of phenol is attached to an sp2 carbon that is more
electronegative than the sp3 carbon to which the OH group of alcohol is attached.
Greater inductive electron withdrawal by the carbon stabilizes the conjugate base by
decreasing the electron density of its negatively charged oxygen.
O O OO-
Resonance structures of phenolate ion
OH
H+
+
phenol
The substituent attached to phenol ring affect the acidic character of it.
- electron donating group decreases the acidity because of less stabilization of
phenoxide ion intermediate
- -electron withdrawing substituent such as nitro group shows substantial change
in acidity.
41. Question
• Which of the following compounds is more acidic?
• A) o-Cresol
• B) o-Chlorophenol
• C) o-Methoxyphenol
• D) o-nitrophenol
• E) m-nitrophenol
42. PHENOL - REACTIONS OF THE OH GROUP
Water phenol is a weak acid
it dissolves very slightly in water to form a weak acidic solution
it is a stronger acid than aliphatic alcohols
the ring helps weaken the O-H bond and stabilises the resulting anion
C6H5OH(aq) C6H5O¯(aq) + H+(aq)
NaOH phenol reacts with sodium hydroxide to form a salt - sodium phenoxide
it is ionic and water soluble
C6H5OH(aq) + NaOH(aq) ——> C6H5O¯ Na+(aq) + H2O(l)
Sodium phenol reacts with sodium to form an ionic salt - sodium phenoxide
hydrogen is also produced
this reaction is similar to that with aliphatic alcohols such as ethanol
2C6H5OH(s) + 2Na(s) ——> 2C6H5O¯ Na+(s) + H2(g)
43. Physical properties and acidic character
The physical properties of phenols are strongly influenced by the hydroxyl group, which
permits phenols to form hydrogen bonds with other phenol molecules and with
polar molecules like water, alcohol and carboxylic acid.
Phenols have higher melting points and boiling points.
Phenols are more soluble in water than arenes and aryl halides of comparable
molecular weight.
The hydroxyl oxygen is less basic (less electron density), and the hydroxyl proton
more acidic, in phenols than in alcohols.
O
H
O
H
O
H
O
H
O
H
Intermolecular H-bonding - phenol
O
Intermolecular H-bonding - aq. phenol
H
O
H
O
H
O
H O
H
OH
H O H
H
O
H
H
O
H
H
Intramolecular H-bonding - o-nitrophenol, salicylic acid
O H
N O
O
O H
O
O
H
44. Preparation of phenols
Pyrolysis of sodium benzene sulfonate
phenol
H+
HO+
Na-
OHO3S NaO3S
NaOH
3500
NaOH
H2O H2O
In this process, benzene sulfonic acid is reacted with aqueous sodium hydroxide.
The resulting salt is mixed with solid sodium hydroxide and fused at a high
temperature. The reaction proceeds by the addition-elimination mechanism of
nucleophilic aromatic substitution.
45. Preparation of phenols
Dow process
Cl
phenol
HO
3000
/3000 psi
dilute NaOH
1-chlorobenzene
In the Dow process, chlorobenzene is reacted with dilute sodium hydroxide at
300°C and 3000 psi pressure. It is Nucleophilic substitution reaction.
46. Preparation of phenols
Air oxidation of cumene
HO
phenol
H
H3C CH3
cumene
O2
100-1300
O
H3C CH3
O H
H3O+ O
H3C CH3
+
Cumene
hydroperoxide
The mechanism for the formation and degradation of cumene hydroperoxide is
given below. The cumene hydroperoxide was formed by a free radical chain
reaction. A radical initiator abstracts a hydrogen from cumene lead to formation of
a tertiary free radical. The creation of the tertiary free radical is the initial step in the
reaction.
H
H3C CH3
cumene
O2
100-1300
O
H3C
CH3
O H
+
Cumene
hydroperoxide
+ R
-RH
H3C CH3
O
H3C CH3
O
H
H3C CH3
cumene
+
H3C CH3
Initiation
47. Preparation of phenols
Air oxidation of cumene
The cumene hydroperoxide undergoes degradation in presence of acid catalyst. In
the first step, a pair of electrons on the oxygen of the hydroperoxide’s “hydroxyl
group” is attracted to a proton of the H3O+ molecule, forming an oxonium ion
which undergoes dehydration forming new oxonium ion. A phenide ion shift to
the oxygen atom (which creates a tertiary carbocation) stabilizes the positively
charged oxygen. The carbocation is stabilized by an acid-base reaction with a water
molecule, leading to the formation of an intermediate which undergoes degradation
in presence of acid catalyst forming phenol and acetone.
HO
phenol
O
H3C CH3
O H
O
H3C CH3
+
Cumene
hydroperoxide
H+ O
H3C CH3
O
H
H
O+
H3C CH3
O
HH+
H3C
CH3
O
O
HH
CH3
CH3O
O
HH
CH3
CH3O
O H -H+
CH3
CH3O
O H H+
H
oxonium ion
48. Preparation of phenols
Synthesis from aniline
HO NO2
3-nitrophenol
H2N NO2
1. NaNO2, H2SO4, H2O
2. H2O, heat
3-nitrobenzenamine
The most important synthesis of phenols in the laboratory is from amines by
hydrolysis of their corresponding diazonium salts, as shown below.
49. Reactions of phenols
Isomerisation
HO
phenol
(enol form - stable)
O
H H
(keto form)
[Tautomerism of phenol]
Phenol is unusual in that its enol tautomer is more stable than its keto tautomer
because the enol tautomer is aromatic, but the keto tautomer is not.
50. Reactions of phenols
Although a hydroxyl group strongly activates an aromatic ring toward electrophilic
attack, an oxyanion substituent is an even more powerful activator. Electron
delocalization in phenoxide anion leads to increased electron density at the
positions ortho and para to oxygen.
-
O
phenoxide
HO
phenol
+H+
O O O
Resonance stabilization of
negative charge
51. Reactions of phenols
Electrophilic substitution reactions
HO
phenol
+ Y+
OH
OH
OH
H
Y
Y
H
Y H
ortho
meta
para
OH
H
Y
OH
H
Y
OH
H
Y
OH
OH
Y
H
Y H
OH
OH
Y
H
Y H
OH
Y H
Relatively
stable
Relatively
stable
The electrophile attacks either on hydroxyl oxygen or the aromatic ring, therefore
the reactions of phenols classified in two types – electrophilic aromatic substitution
and O – substitution reactions.
The –OH group is activating so the electrophilic substitution occurs at o- and or p-
position rather than meta-position which can be explain by the stabilization of
intermediate cation as below.
52. Reactions of phenols
HO
phenol
Br2
Br2
ClCH2
CH2
Cl
00
H2O, 250
HO
HO
Br
Br
Br Br
4-bromophenol
2,4,6-tribromophenol
Bromination
Nitration
HO
NO2
HO
HNO3
acetic acid
50O2N
4-nitrophenol
+
2-nitrophenol
Sulfonation
HO
SO3H
H2SO4 1000
+ HO
SO3H
Friedel-Crafts alkylation
HO
C(CH3)3
(CH 3
) 3
COH
H 3
PO 4
, 60
0
Friedel-Crafts acylation
Cl
O
HO
O
OH O
+
AlCl3
(74%) (16%)
53. Reactions of phenols
Nitrosation:
On acidification of aqueous solutions of sodium nitrite, the nitrosonium ion (:N≡O+)
is formed, which is a weak electrophile and attacks the strongly activated ring of a
phenol. The product is a nitroso phenol
OH
HNO2, H2SO4, H2O
00
C
OH
N
O
naphthalen-2-ol
1-nitrosonaphthalen-2-ol
(99%)
54. Reactions of phenols
Reaction with arenediazonium salts:
Adding a phenol to a solution of a diazonium salt formed from a primary aromatic
amine leads to formation of an azo compound. The reaction is carried out at a pH
such that a significant portion of the phenol is present as its phenoxide ion. The
diazonium ion acts as an electrophile toward the strongly activated ring of the
phenoxide ion.
OH
00
C
OH
N
N
naphthalen-2-ol
C6H5N2Cl
C6H5
(E)-1-(phenyldiazenyl)
naphthalen-2-ol
OH
N
N
C6H5
+
(Z)-1-(phenyldiazenyl)
naphthalen-2-ol
55. Reactions of phenols
Kolbe–Schmitt carboxylation reaction (synthesis of aspirin):
The best known aryl ester is O-acetylsalicylic acid, better known as aspirin. The first
step in the industrial synthesis of aspirin is known as the Kolbe–Schmitt
carboxylation reaction.
The phenolate ion reacts with carbon dioxide under pressure followed by the
treatment of acid to form o-hydroxybenzoic acid, also known as salicylic acid.
Acetylation of salicylic acid with acetic acid anhydride forms acetylsalicylic acid
(aspirin)
O O
O-
Salicylic acid
O
O
O
HO
phenol
base
-
O
phenoxide
+ O C O
pressure
H+
OH O
OH
Acetyl salicylic acid
aspirin
O O
OH
O
OH O
O-
H
56. Reactions of phenols
The Kolbe–Schmitt reaction is an equilibrium process governed by thermodynamic
control.
Salicylate anion
HO
phenol
HO
O
O-
base
-
O
phenoxide
+ O C O
OH O
O-
rather
than
O O-
O
H
strong base: ka
of conjugate acid,
10-10
weakest base: ka
of conjugate acid,
1.06 x 10-3
a base: ka of conjugate
acid, 3.3 x 10-5
p-hydroxybenzoate
anion
intra-molecular Hydrogen
bonding in salicylate anion
57. Reactions of phenols
Synthesis of aryl ethers:
Aryl ethers are best prepared by the Williamson method. Alkylation of the
hydroxyl oxygen of a phenol takes place readily by treating a phenoxide anion with
an alkyl halide. The synthesis is normally performed only by heating a solution of
the phenol and alkyl halide in the presence of a suitable base such as potassium
carbonate.
Allyl aryl ethers undergo an interesting reaction, called the Claisen
rearrangement, on being heated. The allyl group migrates from oxygen to the ring
carbon ortho to it.
HO
phenol
+
base
-
O
phenoxide
SN2 O
allyl phenyl ether
Br
K2CO3
acetone
allyl
bromide
HO
phenol
+
O
allyl phenyl ether
Br
K2CO3
acetone
allyl
bromide
HO
o-allyl phenol
(73%)
*
*
O
*
O
*
H
rearrangement
aromatization
*
58. Reactions of phenols
Acylation of phenol
Acylation agents, such as acyl chlorides and carboxylic acid anhydrides, can react with
phenols either at the aromatic ring (C-acylation) or at the hydroxyl oxygen (O-acylation):
O
R
O
OH O
R
HO
R Cl
O
+
phenol
O
R O R
O
+
Aryl ester
(O-acylation)
HO
O
R
Aryl ketones
(C-acylation)
Friedel Craft reaction
In the absence of aluminum chloride (lewis acid), however, O-acylation occurs instead.
HO
C7H15 Cl
O
+
NaOH/H2O O
O
C7H15
+ HCl
phenol phenyl octanoate
OH O
O
O
+
O
O
+ sodium acetate
H2SO4
F F
4-fluorophenol 4-fluorophenyl acetate
(84%)
HO OH O
O
O
+
NaOH/H2O
2
O O
O
O
+ sodium acetate
resorcinol 1,3-diacetoxybenzene
Acid anhydride to a more powerful acylating agent by protonation of one of its carbonyl
oxygens. Addition of a few drops of sulfuric acid is usually sufficient.
59. Synthesis of aryl ethers:
the Fries rearrangement
The C-acyl isomers are more stable, which will be formed more effectively by
using aluminum chloride as catalyst. It is more effective catalyst for the conversion
of aryl esters to aryl ketones. This isomerization is called the Fries rearrangement.
O
C6H5
O
OH O
C6H5
HO
O
C6H5
AlCl3
+
phenyl benzoate o-hydroxybenzophenone p-hydroxybenzophenone
(9%) (64%)
60. Give each of the following compounds a systematic name, and indicate whether
each is a primary, secondary, or tertiary alcohol:
OH
HO
OH
Cl
OH OH Cl
OH
(a) (b) (c)
(d)
(e) (f)
61. • Write structural formulas for each of the following compounds:
(a) Pyrogallol (1,2,3-benzenetriol) (c) 3-Nitro-1-naphthol
(b) o-Benzylphenol (d) 4-Chlororesorcinol
65. Problems
Give the major product obtained of the following reactions -
(a)
(b)
(c)
(d)
OH
OCH3
+ Br K2CO3
acetone
ONa
+
OH
Cl OH
CHO
HO
OCH3
HNO3, acetic acid, heat
H
N
O
O
heat
67. Reactions of phenols
• Write a balanced chemical equation for each of the following reactions:
(a) Phenol - sodium hydroxide
(b) Product of part (a) + ethyl bromide
(c) Product of part (a) + butyl p-toluenesulfonate
(d) Product of part (a) + acetic anhydride
(e) o-Cresol + benzoyl chloride
(f) m-Cresol + ethylene oxide
(g) 2,6-Dichlorophenol + bromine
(h) p-Cresol + excess aqueous bromine
68. (a) (b) (c) (d)
(e) (f)
ONa O
(g) (h)
O
S
O
O
O
O
O
O
O
OH OH
Cl
Cl
Br
OH
Br
Br
69. Give the product formed from the reaction of each of the following alcohols with
a. an acidic solution of sodium dichromate:
b. the reagents required for a Swern oxidation:
1. 3-pentanol
2. 2-methyl-2-pentanol
3. Cyclohexanol
4. 1-pentanol
5. 2,4-hexanediol
6. 1,4-butanediol
70. Write chemical equations, showing all necessary reagents, for the preparation of 1-
butanol by each of the following methods:
(a) Hydroboration–oxidation of an alkene
(b) Use of a Grignard reagent
(c) Use of a Grignard reagent in a way different from part (b)
(d) Reduction of a carboxylic acid
(e) Reduction of a methyl ester
(f) Reduction of a butyl ester
(g) Hydrogenation of an aldehyde
(h) Reduction with sodium borohydride
71. Write structural formulas for each of the following compounds:
(a) Pyrogallol (1,2,3-benzenetriol) (c) 3-Nitro-1-naphthol
(b) o-Benzylphenol (d) 4-Chlororesorcinol
72. Which is the stronger acid in each of the following pairs? Explain your reasoning.
(a) Phenol or p-hydroxybenzaldehyde
(b) m-Cyanophenol or p-cyanophenol
(c) o-Fluorophenol or p-fluorophenol
73. Write a balanced chemical equation for each of the following reactions:
(a) Phenol _ sodium hydroxide
(b) Product of part (a) + ethyl bromide
(c) Product of part (a) + butyl p-toluenesulfonate
(d) Product of part (a) + acetic anhydride
(e) o-Cresol + benzoyl chloride
(f) m-Cresol + ethylene oxide
(g) 2,6-Dichlorophenol + bromine
(h) p-Cresol + excess aqueous bromine
