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Chapter 12 Functional Groups II and

Nomenclature II

Functional group

= “a group of atoms where the reaction takes place”

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12.1 Aromatic Hydrocarbons: arenes

Complete definition of aromatic compound: Ch 16

Aromatic = 향기로운 , 향기높은

strong odor & unusually stable (because of the conjugated p orbitals)

non-polar, high mp, wide occurrence in nature

BenzeneNot cyclohexatriene

TolueneNot methylbenzene

Naphthalene

CH3 Very stable

isolated very early days of organic chemistry before the systematic names are made

Basic nomenclature

1. parent name: benzene, toluene, naphthalene etc.

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2. The ring is numbered in the same manner as the ring

of cyclohexane

① No number is needed if only one group is attached to the ring

② For rings with multiple substituents, begin numbering at one

substituent and proceed in the direction that gives the lowest numbers to

the remainingCH2CH2CH2CH3

CH3CH

H3C CH2CH3

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4-butyl-1-ethyl-2-isopropylbenzene

3. disubstituted: o-, m-, p- or numbering (1,2-, 1,3-, 1,4-)

1

2

ortho-, o-

1

3

meta-, m-

1

4

para-, p-

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CH3

CH2CH2CH3

m-propyltoluene

or 3-propyltoluene

Example

4. as substituents: phenyl (Ph), benzyl (Bn), tolyl

CH3

CH3

p-dimethybenzene

or 1,4- dimethybenzene

Common name = p-xyrene

CH2

phenyl benzyl

biphenyl

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Physical properties of benzene

melting point boiling point (oC)

Benzene 5.5 80

Cyclohexane 6.5 80

Hexane -94 69

Symmetric shape gives higher melting temp.

Interaction between the molecules determine the boiling point

Reactivity of benzene lower than alkene

R-CH=CH-R + Cl2 R-CHCl-CHCl-R

Benzene + Cl2 No rxn

+ Cl2 + AlCl3 (Lewis acid) Chlorobenzene + HCl

Cl2 + AlCl3 = Cl+ -AlCl4

More electrophilic

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Conjugated p orbitals very stable

found in a wide variety of natural source

Ex)

1) Benzene 1825 Michael Faraday

Oil residue condensed from gas

To light the street lamps of London

2) Estrone: femaile sex hormone ( 469)

3) benzo[a]pyrene carcinogen

After smoking, burned food

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practice: 468, Problem 12.1 & 12.2

Focus On: 469, structure proof for dibromobenzene

Application of benzene obtained from cracking

1) Solvent

2) Production of styrene Polystyrene

3) o-Xyrene, p-xyrene, toluene, cumene (isopropyl benzene); solvent

CH2=CH

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12.2 Phenols

1. 3 x 109 lbs/yr: large production

2. Application; disinfectant, bisphenol A (polymer)

3. Stronger acid (pKa 10) than alcohols (16) Problem 11.5

practice: 472-3, Problem 11.3 ~ 11.6

Having a hydroxy group bonded directly onto an aromatic ring

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Parent name: phenol or other common names

phenol catechol phloroglucinol

OH OH

OH

OH

OH

HO OH

Cl

OH

CH3m-chlorophenol p-methylphenolp-cresol

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12.3 Aldehydes & Ketones

Nomenclature: the longest chain with the carbonyl group

alkanal / alkanone: 474 & 475

H3C H

O

H3C CH3

O

Ph H

O

PhC

CH3

O

acetaldehyde acetone acetophenonebenzaldehyde

carbonyl group

CH3CH

Oethanal or acetaldehyde from acetic acid

CH3CH2CHCH2CH2CHOBr

4-bromohexanal

CH2=CCH2CH2CH

CH2CH3 O4-ethyl-4-pentanal (double bond must be part of a root chain)

Carbon-oxygen double bond

Aldehyde: one hydrogen atom bonded to the carbonyl groupKetone: both of the atoms bonded to the carbonyl group must be carbons

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CHO

Benzaldehyde derived from benzoic acid

CHO

CH32-methylcyclopentanecarboxaldehyde

CH3CCH3

Oacetone (common) or 2-propanone

CH3CCH2C=CHCH3

O CH3

4-methyl-4-hexen-2-one or 4-methylhex-4-en-2-one

O

H3C

5-methyl-2-cyclohexen-1-one (ketone have the priority, double bond have lower #)

OO1,3-cyclohexendione

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acidic -carbon: pKa 20

Properties of aldehyde

polarity: alcohol > aldehyde > ether (boiling point is in the same order)

H-bonding No H-bonding

aldehyde can be oxidized to carboxylic acid, while ketone cannot (see 381, why? Study in ch 19).

See 45

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Application of aldehyde and ketones 476-7

pleasant odors perfumes and flavoring

1) citral: lemon odor found in lemon and orange

2) cinnamaldehyde: strong cinnamon odor found in cinnamon

3) vanillin: vanilla odor, component of natural vanilla

4) camphor: from camphor tree liniments and inhalants ( 감염 , 통증 ,가려움증 완화 )

5) Muscone : from musk ( 사향 )

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12.4 Carboxylic Acids: RCO2Hcarbonyl (C=O) + hydroxy (OH)

CH3CHCH2CH2CH2COH

ph O5-phenylhexanoic acid

HC CCH2COHO

3-butynoic acid

COHO

Cl 2-chlorocyclopentanecarboxylic acid

CO2H benzoic acid

Root with the carboxyl group at one end with the suffix –oic acid is added

Cyclic compounds with the carboxy group attached to the ring use the name of the ring with the suffix- carboxylic acid

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Properties

more polar & hydrogen bonding: high mp & bp

acidic proton: pKa 5

AcOH ( 3 x 109 lbs/yr), aspirin, ibuprofen( 항염증제 ): 479

OH

OHO2C CO2HHO2C CO2H

phenylacetic acid

carboxyl group

terephthalic acidmalonic acid

Natural carboxylic acid

Ant (Latin: fomica) formic acid HCO2H

Vinegar (Latin: acetum acetic acid CH3CO2H

Butter (Latin: butyrum) butyric acid CH3(CH2)2CO2H, from rancid butter

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12.5 Carboxylic Acid Derivatives (I): RCO-Y

• parent name: alkan(o)ic acid

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acryloyl chloride

Cl

O

OO O O

O

succinic anhydride ethyl acetate

H N

O

CH3CN HO ONa

O O

NH2

N,N-dimethylformamide acetonitrile monosodium glutamate (MSG)

practice: 483, Problem 12.14~15

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Acid chloride

----ic acid ---yl chloride

CH3CCl

O

Acetic acid Acetyl chloride

Ethanoic acid Ethanoic chloride

CH3CH=CHCCl

O

+

Acid anhydrideLoss of water

CH3COH

O

HOCCH3

O2-butenoyl chloride

-H2OCH3COCCH3

O OAcetic anhydride

Ethanoic anhydride

---ic anhydride

CH3COH

O

COC

OO

Benzoic anhydride benzoic acid

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Ester

R OH + HOCR'

O

ROCR'O

-H2O----yl ---ate

AlcoholCarboxylic acid

CH3CH2CH2OC

O

H3C

COCH2CHCH2CH3

O CH3

(2-methylbutyl) 3-methyl-1-cyclohexanecarboxylate

Propyl benzoate propanol + benzoic acid

2-methylbutanol + 3-methyl-1-cyclohexanecarboxylic acid

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Amide

R COHO

R CNH2

O

R CNHR'O

R CNR'2O

Primary amide

Secondary amide

Tertiary amide

----e ---amide CH3CH2CH2CH2CH3 CH3CH2CH2CH2CNH2

O

Pentane pentanamide

CH2=CHCHCH=CHCNHCH2CH3

CH3 O

N-ethyl-4-methyl-2,5-hexdienamide

--ic acid, --oic aicd ---amide

HC

O

NCH3

CH3

NCH3

CH3

CO

H3C

N,N-dimethylformaide (DMF)

N,N-dimethylacetamide (DMAc)

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Nitrile or cyano group

CN CNH2

O

COH

O-H2O +NH3

-H2O

---- ---nitrile

----oic acid

----ic acid ---nitrile

1)

2)

Complex compound cyano

CH3C CCH2C N 3-pentynenitrile

CN Benzonitrile benzoic acid

COCH3NC

OMethyl 4-cyanobenzoate (priority)

see p. 490 table 11.3

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Carboxylate salt carboxylate anion + cation

RCO

O

M

CH3CO

ONa

CH3

CO2NH4

Sodium acetate Ammonium 3-methylbenzoate

characteristics: mp & bp

Polarity , bp & mp interaction Order: HC < ether < ester < aldehyde < ketone

< alcohol < carboxylic acid < amide

H-bonding

amides: charged resonance structure

very polar, highest mp and bp

--ic acid cation ---ate

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Acid halide, acid anhydride, and nitrile rare in nature

too reactive with water

Ester and amide abundant in nature relatively stable

485-6

Ester; pleasant order of fruit and flower

isopentyl acetate (CH3CO2CH2CH2CH(CH3)2 : banana odor

methyl butanoate (CH3CH2CH2CO2CH3): rum (liquor), 당밀 , 사탕수수를 발 효 시킨 액체 향

fat: ester glycerol + octadecanoic acid (= stearic acid) 485

Amide; physiological activity

acetaminophen: pain reliever

diethylamide of lysergic acid: hallucinigen ( 환각제 )

DMF and DMAc: aprotic polar sovent

no acidic proton but very polar even some salts can be

dissoved

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Elaboration: fragrance & flavor, 486~7

–hydrolysis of ester & oxidation of aldehydes Carboxylic acid

Ester, aldehyde, ketone: pleasant odor

major component of natural scent and flavors

isopentenyl acetate: juicy fruit gum

ethyl phenylacetate: honey

benzyl acetate + -pentylciccamaldehyde: jasmine

butanal: buttery

Acid: undesirable odor

major component of natural scent and flavors

butanoic acid: rancid butter

hexanoic acid (=caproic acid): smell of goat

2-methylpropanoic acid: component of sweat

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12.6 Sulfur and phosphorus CompoundSulfur

directly beneath oxygen in the periodic table similar to oxygen

d-orbital: six bonds are possible

RSH: thiols (mercaptans); alkanethiol

CH3CH(CH3)CH2CH2-SH: 3-methyl-1-butanethiol

stinky odor, stronger acid, better nucleophile

R-S-R’: sulfides; alkylalkyl sulfide (CH3-S-CH3: dimethyl sulfide)

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sulfoxides & sulfones: DMSO & dimethyl sulfoxide

sulfonic acids: strong organic acid,

derivatives: similar to those of carboxylic acids

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Phosphorus: P

NH3: amine nitrogen PH3:phosphine phosphorus

PH3 phosphine P

O

O

O

O phosphate P

O

OH

OH

HO phosphoric acid

(H3PO4)

triphenyl phosphine: PPh3 P

O

OR

OH

RO

Dialkyl hydrogen phosphate

PH3: phosphine, a toxic gas with bad odor

PPh3: good nucleophile & transition metal ligand

(RO)2P(O)OH: phosphate, backbone for RNA/DNA

phosphatidylcholine: constituent of membranes

practice: 491 Problem 12.17~18

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12.7 Nomenclature of Compounds with Several Functional Groups

CC-OH :–ynol C=C-C=C-CO- : dienone

priority 492 Table 12.3, next page

High priority, in the suffix

CH3CHCH2CCH2CH3

OH O

CH3CHCH2CCH2CH3

O O

CH3CHCH=CHCHCH2CH

OH CN O

5-hydroxy-3-hexanone

Ethyl 3-oxobutanoate

3-cyano-6-hydroxy-4-pentenal

O

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Common name:

often more convenient for very complicated compounds, 494