Transcript Ethers and Epoxides

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Nomenclature of Ethers,
Aldehydes, Ketones,
Carboxylic Acids, and
Esters
Ethers and Their Relatives
• An ether has two organic groups (alkyl, aryl, or vinyl)
bonded to the same oxygen atom, R–O–R
• Diethyl ether is used industrially as a solvent
• Tetrahydrofuran (THF) is a solvent that is a cyclic ether
• Thiols (R–S–H) and sulfides (R–S–R) are sulfur (for
oxygen) analogs of alcohols and ethers
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Naming Ethers
• Simple ethers are named by identifying the two organic
substituents and adding the word ether
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Naming Ethers, continued
•If other functional groups are present, the ether part is
considered an alkoxy substituent
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18.9 Crown Ethers
• Large rings consisting repeating (-OCH2CH2-) or similar
units
• Named as x-crown-y
– x is the total number of atoms in the ring
– y is the number of oxygen atoms
– 18-crown-6 ether: 18-membered ring
containing 6 oxygens atoms
• Central cavity is electronegative and attracts cations
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18-Crown-6
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Uses of Crown Ethers
• Complexes between crown ethers and ionic salts are
soluble in nonpolar organic solvents
• Creates reagents that are free of water that have useful
properties
• Inorganic salts dissolve in organic solvents leaving the
anion unassociated, enhancing reactivity
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18.10 Thiols and Sulfides
• Thiols (RSH), are sulfur analogs of alcohols
– Named with the suffix -thiol
– SH group is called “mercapto group”
(“capturer of mercury”)
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Sulfides
• Sulfides (RSR), are sulfur analogs of ethers
– Named by rules used for ethers, with
sulfide in place of ether for simple
compounds and alkylthio in place of alkoxy
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Aldehydes and Ketones
• Aldehydes and ketones are characterized by the the
carbonyl functional group (C=O)
• The compounds occur widely in nature as intermediates
in metabolism and biosynthesis
• They are also common as chemicals, as solvents,
monomers, adhesives, agrichemicals and
pharmaceuticals
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Naming Aldehydes and Ketones
• Aldehydes are named by replacing the terminal -e of the
corresponding alkane name with –al
• The parent chain must contain the CHO group
– The CHO carbon is numbered as C1
• If the CHO group is attached to a ring, use the suffix
See Table 19.1 for common names
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Common Name of Some Simple Aldehydes
Formula
Common Name Systematic Name
HCHO
Formaldehye
Methanal
CH3CHO
Acetaldehyde
Ethanal
Propionaldehyde
Propanal
CH3CH2CH2CHO
Butyraldehyde
Butanal
CH3CH2CH2CH2CHO
Valeraldehyde
Pentanal
Acrolein
Propenal
Benzaldehyde
Benzenecarbaldehyde
CH3CH2CHO
H2C=CHCHO
PhCHO
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Naming Ketones
• Replace the terminal -e of the alkane name with –one
• Parent chain is the longest one that contains the ketone
group
– Numbering begins at the end nearer the
carbonyl carbon
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Ketones with Common Names
• IUPAC retains well-used but unsystematic names for a
few ketones
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Ketones and Aldehydes as Substituents
• The R–C=O as a substituent is an acyl group is used
with the suffix -yl from the root of the carboxylic acid
– CH3CO: acetyl; CHO: formyl; C6H5CO:
benzoyl
• The prefix oxo- is used if other functional groups are
present and the doubly bonded oxygen is labeled as a
substituent on a parent chain
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The Importance of Carboxylic Acids
(RCO2H or RCOOH)
• Starting materials for acyl derivatives (esters, amides,
and acid chlorides)
• Abundant in nature from oxidation of aldehydes and
alcohols in metabolism
– Acetic acid, CH3CO2H, - vinegar
– Butanoic acid, CH3CH2CH2CO2H (rancid
butter)
– Long-chain aliphatic acids from the
breakdown of fats
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20.1 Naming Carboxylic Acids and
Nitriles
• Carboxylic Acids, RCO2H
• If derived from open-chain alkanes, replace the terminal
-e of the alkane name with -oic acid
• The carboxyl carbon atom is C1
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Alternative Names
• Compounds with CO2H bonded to a ring are named
using the suffix -carboxylic acid
• The CO2H carbon is not itself numbered in this system
• Use common names for formic acid (HCOOH) and acetic
acid (CH3COOH) – see Table 20.1
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Common Names
– common names are based on natural
origin rather than structure
O
HCOH
Systematic Name Common Name
methanoic acid
formic acid
ethanoic acid
acetic acid
octadecanoic acid
stearic acid
O
CH3COH
O
CH3(CH2)16COH
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More Common Names
Systematic Name Common Name
O
CH3CHCOH
OH
2-hydroxypropanoic
acid
O
CH3(CH2)7
(CH2)7COH
C
H
lactic acid
C
H
(Z)-9-octadecenoic
acid
oleic acid
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Common Diacids
O
C
OH
O
C
OH
C
OH
C
C
OH
O
OH
C
CH2
CH2
CH2
CH2
OH
O
C
CH2
OH
O
Oxalic
Malonic
Succinic
Glutaric
OH
CH2
CH2
CH2
C
O
OH
O
CH2
CH2
C
O
O
O
C
OH
Adipic
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Nitriles, RCN
R C N or RCN
• Closely related to carboxylic acids named by adding nitrile as a suffix to the alkane name, with the nitrile
carbon numbered C1
• Complex nitriles are named as derivatives of carboxylic
acids.
– Replace -ic acid or -oic acid ending with onitrile
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Naming Esters, RCO2R
• Name R’ and then, after a space, the carboxylic acid
(RCOOH), with the “-ic acid” ending replaced by “-ate”
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