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平成27年度有機化学IV
前半第四回目講義
宮地弘幸
カルボン酸アミド誘導体
カルボン酸アミドの命名法
Amides are named alkanamides, cyclic amides are lactams.
Amides are called alkanamides, the –e in alkane having been replaced by –amide.
In the common names, -ic is replaced by –amide.
In cyclic systems, –carboxylic acid is replaced by –carboxamide.
Nitrogen substituents are indicated by the prefix N- or N,N-.
Amides can be primary, secondary or tertiary.
Derivatives of carbonic acid, H2CO3,
include ureas, carbamic acids and
carbamic esters.
カルボン酸アミドの命名法
Cyclic amides are called lactams. The systematic name is aza-2cycloalkanones. The naming rules follow those used for lactones.
アミドの酸加水分解でカルボン酸が生成
Amide hydrolysis requires strong heating in a concentrated
acid or base.
Amides are the least reactive of the carboxylic acid derivatives.
Nucleophilic addition-elimination reactions of amides generally require
relatively harsh conditions.
アミドのアルカリ加水分解でカルボン酸イオンとアミンが生成
Basic hydrolysis produces the carboxylate salt and the amine.
アミドはアミンまたはアルデヒドに還元される
Amides can be reduced to amines or aldehydes.
Unlike alcohols, reduction of amines using LiAlH4 produces amines instead of
alcohols.
アミドはアミンまたはアルデヒドに還元される
Reduction of amides using bis(2-methylpropyl) aluminum hydride produces
aldehydes, the same as the reaction with esters.
ホフマン転移：アミドから一炭素減ったアミン合成
Amidates and Their Halogenation: The Hofmann Rearrangement
In amides, the hydrogens on both the nitrogen and -carbon are acidic.
Deprotonation of the nitrogen to form an amidate ion is more favorable,
however.
In the presence of a base, a primary amide undergoes a special
halogenation reaction called the Hofmann Rearrangement.
ホフマン転移：アミドから一炭素減ったアミン合成
ホフマン転移：アミドから一炭素減ったアミン合成
When the alkyl group is chiral, its original stereochemistry is retained during
the course of the rearrangement.
ニトリル（アルカンニトリル）の命名法
Nitriles, RCN, are considered derivatives of carboxylic acids because the
carbon atom is in the same oxidation as the carboxy-carbon, and nitriles can
be converted into other carboxylic acid derivatives.
In IUPAC nomenclature, nitriles are named from alkanes.
The systematic naming of nitriles is as alkanenitriles. The –ic acid ending of
the carboxylic acid is usually replaced with
–nitrile.
ニトリル（アルカンニトリル）の命名法
The chain is numbered as in carboxylic acids.
Similar rules apply to dinitriles derived from carboxylic acids.
As a substituent, -CN is called cyano.
Cyanocycloalkanes are called cycloalkanecarbonitriles.
The common name, benzonitrile, is generally used rather than the
systematic benzenecarbonitrile.
ニトリル構造はアルキン構造に類似
The CN bond in nitriles resembles the CC bond in alkynes.
Both atoms in the nitrile group are sp hybridized with a lone electron pair
occupying an sp orbital pointing away from the molecule along the C-N axis.
In the IR spectrum, the CN stretching vibration appears at about 2250 cm1 (the same range as CC, but more intense).
The 13C NMR absorption for the nitrile carbon is at a lower field (~112-126
ppm) than that of the alkynes (~65-85 ppm) because nitrogen is more
electronegative than carbon.
ニトリルの酸加水分解
Nitriles undergo hydrolysis to carboxylic acids.
Nitriles can be hydrolyzed to carboxylic acids, however, the reaction conditions are
stringent, requiring a concentrated acid or base at high temperatures.
ニトリルの塩基性加水分解
ニトリルは有機金属との反応でケトンを生成
Organometallic reagents attack nitriles to give ketones.
Strong nucleophiles, such as organometallic reagents, add to nitriles to give
anionic imine salts. Work-up with aqueous acid gives the neutral amine,
which is rapidly hydrolyzed to the ketone.
ニトリルのヒドリド還元でアルデヒドが生成
Reduction of nitriles by hydride reagents leads to
aldehydes and amines.
Bis(2-metehylpropyl)aluminum hydride (DIBAL) adds to a nitrile only
once (as with esters and amides) to give an imine derivative.
Aqueous hydrolysis then produces an aldehyde.
ニトリルのヒドリド還元でアミンが生成
Treatment of nitriles with strong hydride-reducing agents results in doublehydride addition, yielding an amine upon aqueous work-up. LiAlH4 is the
best reagent for this purpose.
シャトルカード課題
シャトルカード課題

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