Carbonyl compounds
Acid anhydride 酸酐
Amides
酰胺Carboxylic aci
ds 羧酸
Acid chlorides
酰卤Aldehydes
醛
Esters
酯Ketones
酮
general formula
classgeneral formula
class
R
O
R'
R
O
H
R
O
OH
R
O
OR'
R
O
Cl
R
O
NR1R2
R
O
O R
O
Chapter 10 Aldehydes and Ketones
Text 1: p 774-835
Text 2: p 311-348
Structure of the carbonyl group
C O
120o
120o
120o
1. C-sp2 hybridization
2. The bond angles is 120o.
3. It is a trigonal planar structure
4. The carbon-oxygen double bond consists of a sigma bond and a pi-bond
C O C O
Resonance structures
CHO
Benzaldehyde
(from bitter almonds)
苯甲醛 ( 苦杏仁 )
CHO
OH
OCH3
Vanillin
(from vanilla beans)
香草醛 ( 香草豆 )
CHO
OH
Salicylaldehyde
(from meadowsweet)
水杨醛 ([ 植 ] 绣线菊 )
CH=CHCHO
Cinnamaldehyde
(from cinnamon)
肉桂醛 (3- 苯基丙烯醛) ([ 植物 ] 肉桂 , 桂皮 )
CHO
O
O
Piperonal
(made from safrole;
odor of heliotrope)
胡椒醛由黄樟油精制备 ,
[ 植 ] 向日葵气味
O
Camphor
樟脑
O
*
Carvone 香芹酮( - )薄荷味( + )香菜味 O
Muscone
麝香酮
CH3
O
Acetophenone
苯乙酮乳香味
10.1 Nomenclature of aldehydes and ketones
IUPAC names common names
aldehydes: alkane — alkanal ---ic acid—---aldehyde
ketones: alkane — alkanone alkyl alkyl ketone
H C
O
H H3C C
O
H CH3CH2CHO CH3CH2CH2CHO
Methanal甲醛formaldehyde
Ethanal乙醛acetaldehyde
Propanal丙醛propionaldehyde
Butanal丁醛butyraldehyde
(formic acid) (acetic acid) (propionic acid) (butyric acid)
CH3 CH2 CH CH C
O
H
2-pentenal (pent-2-enal)2- 戊烯醛
benzenecarbaldehyde苯甲醛benzaldehyde
C
O
H
cyclohexanecarbaldehyde环己烷(基)甲醛
C
O
H
2-Naphthalenecarbaldehyde2- 萘甲醛
CHO
CH3CHCH2CHO
Br
3-bromobutanal3- 溴丁醛β-bromobutyraldehyde
H3C
O
CH3
2-propanoneacetone丙酮dimethyl ketone
H3C
O
CH2CH3
2-butanone (butan-2-one)2- 丁酮methyl ethyl ketone
CH3COCH2CH=CH2
4-penten-2-one
4- 戊烯 -2- 酮
CH3CH2 C
O
CH2 CHO
3-oxopentanal
3- 氧代戊醛
C
O
benzophenone
(diphenyl ketone)
二苯甲酮
C
O
OH
CHO
2-formylbenzoic acid
2- 甲酰基苯甲酸
H3C C
O
SO3H
4-acetylbenzenesulfonic acid
4- 乙酰基苯磺酸
C
O
CH3
acetophenone
(methyl phenyl ketone)
苯乙酮
10.2 Physical properties of aldehydes and ketones
Boiling point:
alkane < ether < aldehyde< ketone < alcohol
Solubility in water:
acetone, ethanal are misible (混溶) with water (hydrogen bond)
formaldehyde: 40% aqueous solution (formalin, 福尔马林 )
O
O
OH C H
O
3H+
(gas)
heat
mp: 62 °C
O
O
O
H3C C H
O
3H+
heat
bp: 125 °C
H3C H
CH3
H
H
H3C
bp: 21 °C
trioxane
三聚甲醛paraldehyde
三聚乙醛
10.3 Spectroscopy of aldehydes and ketones
C=O ~1710 cm-1 (O=)C-H 2720, 2820 cm-1
C C C
O
~1685 cm-1
O OO O
ν: 1714 1745 1790 1815 cm-1
n-π*, weak, 280~300 nm;
π -π*, strong, < 200 nm; C=C-C=O, >200 nm
IR
UV
1H NMR: CH2 C CH2
O
δ: 2.4 2.1 9~10CH3 C
O
C H
O1H NMR
13C NMR C=O: ~200 ppm, α-C: 30~40
17
CH3CH2CH2COCH3
209 42
30
14
MS 43
86 71 58
CH3CH2CH2COCH3
γ-H is needed;
m/e: even (偶数 )
O
CCH2
CH2
CH2
H
CH3H3C
CCH2
OH
+CH2
CH2
M = 28
R C O R C O( 1 )
Mclafferty rearrangement ( 麦氏重排 )( 2 )
10.4 Synthesis of aldehydes and ketones
R CHOH[ O ]
R C
2o alcohol ketone
R' R'
O
R CH2OH[ O ]
R CHO R COOH
1o Alcohol Aldehyde Carboxylic acid
[ O ]
1. Aldehydes and ketones from oxidation of alcohols
Oxidants: K2Cr2O7 or Na2Cr2O7 / H2SO4
CrO3/ H2SO4
PCC (Pyridinium chlorochromate, 吡啶三氧化铬 )
PDC (Pyridinium dichromate, 重铬酸吡啶盐 )
2. Aldehydes and ketones from ozonolysis of alkenes
( 2 ) Zn, H2O reduction
R
R'
R''
H
( 1 ) O3, CH2Cl2, -78oC R
R'O O
R''
H+
Aldehydes (È©)
ketones (ͪ £©
3. Aldehydes and ketones from alkynes
HC CH + H2OHgSO4,H2SO4 CH
OH
CH2 CH3 C H
O
R C C HSia2BH
C C
H
R H
BSia2
Sia = CHHC
H3C
H3C
CH3
H2O2 C C
H
R H
O H
C C
H
R H
O
H
OH
4. Aromatic aldehydes and ketones from acylation of benzene derivatives
+ RCOClAlCl3 COR
+ HCl
+ AlCl3 COR+ HCl
O
R
O
RO
G
+ HCl + COAlCl3, CuCl
G
CHO
Gatterman-Koch formylation ( 盖特曼 - 考赫甲酰化反应 )
Friedel-Crafts acylation
5. Synthesis of aldehydes and ketones using 1,3-dithiane
S S
H H
(1) BuLi(2) 1° R-X S S
R H
(1) BuLi(2) 1° R'-X S S
R R'
H3O+, HgCl2 H3O+, HgCl2
R H
O
R R'
O
(H)RC
(H)RO +
H+
- H2OSH SHS S
(H)R R(H)
1,3- dithiane
1,3- 二噻烷(硫缩醛)
6. Synthesis of ketones from carboxylic acids
R C
O
OH
LiOH(or R'-Li)
R C
O
OLi R'-Li
R C
OLi
OLi
R'carboxylic acid
H3O+
R C
OH
OH
R'
-H2OR C
O
R'
ketone
hydrate 水合物
R C
O
OH
carboxylic acidR C
O
R'
ketone
7. Synthesis of aldehydes and ketones from acid chlorides
R C Cl
O
R C R' (H)
O
R C Cl
O
R C H
OLiAlH(O-t-Bu)3
R C Cl
O
R C R'
OR'2CuLi Not RMgX
Not LiAlH4
8. Synthesis of ketones from nitriles ( 腈 jing)
R C N + R'MgX R C
N+ MgX-
R'H3O+
R C
O
R'
R C N + R' Li R C
N+ Li-
R'H3O+
R C
O
R'
R C N R C
O
R'
nitrile
9. Other methods
CH3
MnO2£¬65% H2SO4
CHO
ArCH32Cl2hv
ArCHCl2H2O ArCHO
ArCH3CrO3£¬£¨ CH3CO)2O
ArCH(OCOCH3)2
H2O ArCHO
……………………
Assignments
Problem 18-1, 7, 8, 9, 11
10.5 Reactions of aldehydes and ketones
Nucleophilic addition to the carbon-oxygen double bondReduction and oxidation of aldehydes and ketonesReactions of α-H
R C C
O
R'
H Nuacidity
1. Nucleophilic addition to the carbon-oxygen double bond
RC
R'O + H-Nu
R
CR'
OH
Nu
Nucleophilic atom: C (carbon)
O (oxygen)
N (nitrogen)
S (sulfur)
1). Carbon as nucleophilic atom
( 碳为亲核性原子 )
(1) organometallic reagents addition to C=O
+C6H5MgBr(1) Et2OH3C
CH
O(2) H3O+ C6H5CHOH
CH3
C C
R1
R2
OHCR H3O+
alkynol ( 炔醇 )
C O
R2
R1
R C CNa + C C
R1
R2
OCR Na
(2) The Wittig reaction: the addition of ylide ( 叶立德 ) (18-13)
魏悌希反应
The wittig reaction has proved to be a valuable method for synthesizing alkenes. Wittig was a co-winner of the Nobel prize for chemistry in 1979.
C O
R
(R')H
+ (C6H5)3P-CHR'''
R''
Phosphorus ylideÁ×Ò¶Á¢µÂ
C CR
(R')H
R''
R'''+ O P(C6H5)3
Triphenylphosphine oxideÈý±½»ùÑõì¢
aldehyde ketone
the Wittig reagentalkene
Preparation of phosphorus ylides:
Mechanism:
(C6H5)3P + CH2 Br (C6H5)3P CH2BrR
R
Betaine £¨ÄÚÑΣ©Phosphorus ylide Á×Ò¶Á¢µÂ
(C6H5)3P CHR (C6H5)3P CHRn-BuLi
-HBr
O+(C6H5)3P CH2 CH2
O P(C6H5)3
CH2
O P(C6H5)3
CH2+O P(C6H5)3
Methylenecyclohexane
1° RX are prefered
Problem 18-14
Trimethylphosphine is much less expensive than triphenylphosphine. Why is trimethylphosphine unsuitable for making most phosphorus ylides?
Problem 18-15
(C6H5)3P +
OH3C
H
H
CH3
Predict the products. What is the stereochemistry of the double bond in the product?
(3) The addition of hydrogen cyanide (HCN)
Cyanohydrins
腈醇 , α- 羟基腈
C O + H CN C
OH
CN
O
CCH3H3C
NaCN, H2SO4
OH
CCH3H3C
CN
Cyanohydrins are useful intermediates in organic synthesis.
C
OH
CN
[H]
HCl, H2O
-H2O
C
OH
CH2NH2
C
OH
COOH
CC COOHH2SO4, heat
β-amino alcohol
β- 氨基醇
α-hydroxy acid
α- 羟基酸
α,β-unsaturated acid
α,β- 不饱和酸
C O
H3C
H3C
+ HCN C
H3C
H3C
OH
CN
Cyanohydrinsëæ¼ÇâÇèËá
Hydrogen cyanide
HCl, H2OC
H3C
H3C
OH
COOH
a - Hydroxy acid
a - ôÇ»ùËá
H2SO4
CH3OHCH2C
CH3
COOCH3
- Unsaturated acid ester
CH2 C
CH3
COOCH3
* *n
¾Û±ûÏ©Ëá¼×õ¥2-¼×»ù±ûÏ©Ëá¼×õ¥
For example
2). Oxygen as nucleophilic atom
( 氧为亲核性原子 )
(1) The addition of water to aldehydes and ketones: formation of hydrates( 水合物 )
Hydrate
( a gem-diol) 同碳二醇
RC
R'O +
R'
CR OH
OH
H-OHH+ or -OH
How about the mechanisms ?
Catalysis: acid or base
Reversible reaction
可逆反应 unstable
(2) The addition of alcohols to aldehydes and ketones: Formation of Acetals( 缩醛(酮) )
OHCC=O
ROH, H+ OR +ROH, H ORC
OR+ H2O
hemiacetal 半缩醛 ( 酮 )
acetal 缩醛 ( 酮 )
Catalysis: acid
Reversible reaction
可逆反应
Old use: acetal 缩醛 ketal 缩酮IUPAC: acetal
C=O C=OH+
H+ ROH OR
COH
H
++H OR
COH
OHC
OR +H ORC
OHH
+
H2OOR
C+ROH
ORC
OR
H
+
H+
ORC
OR
Mechanism
Hemiacetal 半缩醛 ( 酮 )
acetal 缩醛 ( 酮 )
Base (-OH) can not catalyze the acetal form
ation. Why?
SN1
Cyclic acetals ( 环状缩酮 ) often have more favorable equilibrium constants than acyclic acetals.
RC
RO +
HCl RC
R
HO
HO O
O
+ H2O
RC
RO
O HCl+ H2O
RC
RO +
HO
HO
CH3CH2CHO + 2 CH3OHH+
H3CH2CHCOCH3
OCH3+ H2O
For example
Use of acetals as protecting groups (保护基) .
C CH(CH2)2CHCH2CHO
CH3
H3C
H3C
CH3OH , H+
C CH(CH2)2CHCH2CH(OCH3)2CH3
H3C
H3C
HCl , H2OHOOC(CH2)2CHCH2CHO
CH3
HOOC(CH2)2CHCH2CH(OCH3)2
CH3
KMnO4
H
Example 1
C CH(CH2)2CHCH2CHO
CH3
H3C
H3C
HOOC(CH2)2CHCH2CHO
CH3
CH3COCH2CH2Br CH3COCH2CH2CHCH3
OH
CH3COCH2CH2BrOH OH
H+ CH3CCH2CH2Br
O O
Mg , Et2O
CH3CCH2CH2MgBr
O O1. CH3CHO
2. H2O , H+
CH3COCH2CH2CHCH3
OH
Example 2
O
O
OCH2CH3O CH2OH
Example 3
O
O
OCH2CH3
HO
HO
HCl
O
OCH2CH3
O
O
1. LiAlH4, (CH3CH2)2O
2. H2OCH2OH
O
O
H+
H2O
O CH2OH
3). Nitrogen as nucleophilic atom( 氮为亲核性原子 )
NH2—H ammonia 氨NH2—R amine 胺 NH2—OH hydroxylamine 羟氨NH2—NH2 hydrazine 肼NH2—NHCONH2 semicarbazine 氨基脲
R'C
R''O + H2N G
R'C
R''N G + H2O
H+
R'C
R''O + H2N R
R'C
R''N R + H2O
H+
(1) Formation of imines ( 亚胺 ) and enamine ( 烯胺 )
H2O
R' C
O
R'' + H2N R R' C R''
O
NH RH
H3O+
R' C R''
OH
HN R
carbinolamine醇胺
H3O+
R' C R''
OH2
HN R
R' C R''
HN R
-H2O
R' C R''
HN R
H2O
R' C R''
N R
Imine 亚胺Shiff base西佛碱
Catalysis: acid
Reversible reaction
可逆反应
R' C
O
CH2R" + HNR
R
H3O+
R' C CHR''
OH
N R
R
HR' C CHR''
N R
R
H3O+
+ H2O
enamine
烯胺2°amine
仲胺
The pH value is crucial to imine formation. Why?
Catalyst: Acid catalyzes the dehydration.
Nu: the nucleophilicity of RNH2 can be weaken in strong acid conditions.
Product: unstable in strong acid conditions.
(2) Condensation with hydroxylamine ( 羟氨 ) and hydrazine ( 肼 )
+ H2NNHC=OH2O C=NNH
NO2
NO2NO2
NO2
2,4-dinitrophenylhydrazine
2,4- 二硝基苯肼2,4-dinitrophenylhydrzone
2,4- 二硝基苯腙
C=N NH2
H2OC=O + H2NNH2
hydrazine 肼 hydrazone 腙
+ H2NOHC=OH2O C=N OH
hydroxylamine 羟胺 oxime 肟
+ H2NNHCNH2C=OH2O C=NNHCNH2
O O
semicarbazide 氨基脲
semicarbazone缩氨基脲
肟、腙、缩氨基脲都是很好的结晶。有固定的熔点。在酸性水溶液中加热分解为原来的醛酮。
可用来鉴别和提纯醛、酮。如实验室常用 2 , 4- 二硝基苯肼鉴别醛、酮。
H3CC
HO + H2N OH
Acetaldehyde
H3CC
HN OH
Hydroxylamine
ôÇ°·
Acetaldehyde oxime
ÒÒÈ©ë¿ÒÒÈ©
+ H2O
H2NNH
Phenylhydrazine
C6H5C
H3CN NHC6H5
Acetophenone phenylhydrazone
Ph
±½ÒÒͪ ±½ëê
CC6H5
H3CO +
Acetophenone
±½ë±½ÒÒͪ
+ H2O
O + H2NNHCNH2
O
NHNHCONH2
Cyclohexanone Cyclohexanone semicarbazone
»·¼ºÍª »·¼ºÍª Ëõ°±»ùëå
+ H2O
Semicarbazide
4). Sulfur as nucleophilic atom硫为亲核原子
R
C
H
O +
HSCH2CH3
HSCH2CH3
R
C
H
SCH2CH3
SCH2CH3
H+
- H2O
ThioacetalThiol 硫醇
(1) Formation of thioacetals ( 硫缩醛和硫缩酮 )
H
C
H
O +H+
- H2OSH SH
S S
H H1,3-dithiane
1 , 3- 二噻烷
(2) The addition of sodium bisulfite (NaHSO3)
产物为很好的结晶,不溶于饱和亚硫酸氢钠溶液。反应可逆,加酸可得原来的醛酮,故好可用于鉴别和提纯醛酮。
Sodium α-hydroxysulfonate
α- 羟基磺酸钠
C O
R
H (R')
+ NaHSO3 C
R
H (R')
OH
SO3Na
另外,用于制备腈醇,避免了直接使用 HCN 。
PhC
HO + NaHSO3
PhC
H
OH
SO3Na
H2O NaCN
H2O
PhC
H
OH
CN
Summary of the nucleophilic addition to C=O bond
1. Types of addition:
Simple addition Addition-elimination
To form C-C, C-O, C-S single bond
To form C=C, C=N double bond
2. Factors affecting the reaction rate:
(1) Steric hindrance ( 空间位阻 )
(2) Electronegative of the substituents (取代基电负性)(3) Nucleophiles (亲核试剂强度)(4) Catalyst ( 催化剂 )
(1) Reactivity: Aldehydes
(2) Ability of forming hydrates:
CH3CH2CHO HCHO Cl3CCHOK: 0.7 40 500
Examples:
(3) Ability of forming cyanohydrins
CH3CHO CH3COCH2CH3 (CH3)3CCOC(CH3)3
K: > 104 38 <=1
(4) The pH is crucial to imine formation
> ketones
Stereochemistry in nucleophilic addition to C=O
(1) The substrate is chiral aliphatic ketone or aldehyde
羰基加成的格拉穆( Cram )规则:
O
R
C C
L
M
S
R'MgX
2. H2O, H+
1. R'MgX
O
R
M S
LR'
OH
L
SM
R
major
R'
OH
L
SM
R
+
minor Asymmetric synthesis
不对称合成
O
H
CH3
1. CH3Li
2. H3O+
H
CH3
OHH3C
+H
CH3
CH3HO
90% 10%
(2) The substrate is cyclic ketones
O
(H3C)3C
H
OH
OH
H(H3C)3C (H3C)3C+
LiAlH4 90% 10%
LiBH(sec-Bu)3 12% 88%
2. Reduction and oxidation of
aldehydes and ketones
1. Reduction of aldehydes and ketones
(1) Reduction of C=O to form alcohols
R'
C
R
O R' C
R
H
OH[ H ]
[ H ]: (a) NaBH4, LiAlH4 ( in laboratory)
(b) Ni-H2, high T, P (in industry)
(c) i-PrOH / (i-PrO)3Al, Meerwein-Ponderf-Verley reaction
CH3 CH
OH
CH3R C
O
R'(i-PrO)3Al
+ CH3 C
O
CH3R CH
OH
R' +
H
O
Ni-H2 H
O
H
OH
Ni-H2
H
(90%)
H
O
H2, 5% Pd/C H
O
H
O
NaBH4, or LiAlH4 H
OHH
(2) Reduction of C=O to form CH2
R'
C
R
O[ H ]
R'
CH2
R
deoxygenation
[ H ]:(a) Zn (Hg), HCl, —the Clemmensen reduction.
(b) NH2NH2; KOH, heat in high boiling point solvent such as DMSO ( 二甲亚砜 ), diethylene glycol ( 一缩二乙二醇 ), etc. —the Wolff-Kishner reduction
The Wolff-Kishner reduction吉日聂尔 - 沃尔夫 - 黄鸣龙反应
C NN
H
HOH
C NN
H C NN
H
H2O
OH
C NN
HH ( + -OH)C NN
H
H2O
CH H
C O H2N-NH2KOH, heat
+HOCH2CH2OCH2CH2OH
CH2 + N2 + H2O
CH( N2 +)
醛、酮和肼反应生成的腙在氢氧化钾或乙醇钠作用下分解放出氮气而生成烃 .
CCH2CH3
O
CH2CH2CH3
NH2NH2 , NaOH
¡÷ (HOCH2CH2)2O
O NH2NH2, KOH, HOCH2CH2OH
heat
(2) Oxidation of aldehydes and ketones
R CO
HR C
O
OH
[ O ]
[ O ] : ( 1 ) K2Cr2O7 or Na2Cr2O7 / H2SO4 ; CrO3/ H2SO4
( 2 ) KMnO4
( 3 ) Ag2O
( 4 ) Ag(NH3)2+, OH- ( Tollens reagent, 托仑试剂)
Tollens test, 银镜反应,区别醛、酮)
R C
O
H + 2 Ag(NH3)2+
+ 3 OHH2O 2Ag + R C
O
OH + 4 NH3 + H2O
Tollens test, 银镜反应
Oxidation of aldehydes
the Baeyer-Villiger oxidation (拜尔 - 魏林格氧化)
Oxidation of ketonesO
HNO3HOOC CH2 COOH4
ketone ester
CO
CH3
Acetophenone
RCOOH
O
O C
O
CH3
Phenyl acetate ÒÒËá±½õ¥
RCOOH
OO
O
O
40 °C
(3) The Cannizzaro reactions 康尼查罗反应
Disproportionation reaction 歧化反应
CHO COONa CH2OH2 +
NaOH, C2H5OH
~50 °CH+
COOH
HCHO + NaOHheat
HCOONa + CH3OH
H C
O
H
O HOHH C
O
H+ H C
O
O + H C H
H
O
H2O
CH3OH+ OH
Mechanism:
H C
O
H + OH H C
O
H
OH
Crossed Cannizzaro reaction 交叉的康尼查罗反应:
HCHO is allways the reductant.
+ HCOONaCHO + HCHONaOH CH2OH
(CH3)3CCHO + HCHONaOH
(CH3)3CCH2OH+ HCOONa
Intramolecular Cannizzaro reaction分子内康尼查罗反应
Intramolecular Cannizzaro reaction分子内康尼查罗反应
Lactone内酯
δ-hydroxyl acidδ- 羟基酸
CHO
CHO
C2H5 (1) NaOH
((2) H+
COOH
CH2OH
C2H5
-H2O
O
C2H5 O
Assignments
Text 1: 18-50, 51, 52, 60, 66
Text 2 (selected): 12, 14, 19
Reactions of aldehydes and ketones
Summary
Nucleophilic addition to the carbon-oxygen double bond
Reactions of α-H: halogenation
Reduction and oxidation of aldehydes and ketones
Name reactions
G
+ HCl + COAlCl3, CuCl
G
CHO
(1) Gatterman-Koch formylation ( 盖特曼 - 考赫甲酰化反应 )
(2) The Wittig reaction: the addition of ylide ( 叶立德 ) (18-13)
魏悌希反应
C O
R
(R')H
+ (C6H5)3P-CHR'''
R''
Phosphorus ylideÁ×Ò¶Á¢µÂ
C CR
(R')H
R''
R'''+ O P(C6H5)3
Triphenylphosphine oxideÈý±½»ùÑõì¢
Summary
(3) Meerwein-Ponderf-Verley reaction
CH3 CH
OH
CH3R C
O
R'(i-PrO)3Al
+ CH3 C
O
CH3R CH
OH
R' +
(5) the Wollf-Kishner reduction 吉日聂尔 - 沃尔夫 - 黄鸣龙反应
O H2N-NH2KOH, heat
+HOCH2CH2OCH2CH2OH
CH2 + N2 + H2O
(4) the Clemmensen reduction
R
R
O
(H, Ph)
Zn (Hg), HCl. reflux
Clemmensen reduction¿ËÀ³ÃÅÉ»¹Ô
R
R(H, Ph)
(H, Ph) (H, Ph)
(6) the Baeyer-Villiger oxidation (拜尔 - 魏林格氧化)
C
O
CH3
Acetophenone
RCOOH
O
O C
O
CH3
Phenyl acetate ÒÒËá±½õ¥
R C
O
H + 2 Ag(NH3)2+
+ 3 OHH2O 2Ag + R C
O
OH + 4 NH3 + H2O
(7) Tollens test, 银镜反应
(8) The Cannizzaro reactions 康尼查罗反应
HCHO + NaOH¡÷
HCOONa + CH3OH
Assignment
• Text 1: 18-35, 37, 50, 60, 66
• Text 2: 12, 14, 19
黄鸣龙 黄鸣龙 1898 年 8 月 6 日出生于江苏省扬州市,于 1979 年 7 月1 日逝世。早年留学瑞士和德国, 1924 年获柏林大学博士学位。 1952 年回国,历任中国科学理化部委员,国际《四面体》杂志名誉编辑,全国药理学会副理事长,中国化学会理事等。 黄鸣龙的一生是为科学事业艰苦奋斗的一生。他发表的论文近 80篇,综述和专论近 40 篇。主要的科研成就概述如下:( 1 )山道年一类物立体化学的研究 : 黄鸣龙最初从事植物化学研究,他博士论文题为 " 植物成分的基本化学转变 " 。稍后,开展延胡素和细辛的研究。其中,延胡索乙素现已在临床上广泛应用。
附录:
1938 年,他在与 lnhoffen 研究用胆固醇改造合成雌性激素时,发现了双烯酚的移位反应。在此基础上,他随后从事山道年一类物的立体化学研究,发现了变质山道年在酸碱作用下,其相对构型可成圈地互相转变,这一发现,轰动了当时的国际有机界。各国学者根据他所解决山道年及其一类物的相对构型,相继推定了山道年一类物的绝对构型。 ( 2 )改良的凯惜纳 - 乌尔夫还原法 : 1946 年,黄鸣龙在美国哈佛大学工作时,在做凯惜纳 - 乌尔夫还原反应时,出现了意外的情况(漏气),但并未弃之不顾,而是照样研究下去,结果得到出乎意外的好产率。于是他仔细地分析原因,并经多次试验后总结如下:
在将醛类或酮类的羧基还原成亚甲基时,把醛类或酮类与 NaOH 或 KOH, 85%(有时可用 50%)水合肼及双缩乙二醇或三缩乙二醇同置于圆底烧瓶中回流 3-4小时便告完成。这一方法避免了凯惜纳 - 乌尔夫还原法要使用封管和金属钠以用难于制备和价值昂贵的无水肼的缺点,产率大大提高。因此,黄鸣龙改良的凯惜纳 - 乌尔夫还原法地国际上应用广泛,并写入各国有机化学教科书中,简称黄鸣龙还原法。后来,他经常以此为例,向青年科技人员说明做实验一定要认真观察实验现象,并一再强调在反应中,出现了异常现象应尽可能地将反应结果弄明白这一实事求是、坚持真理的科学态度。
( 3 )甾体激素的合成和有关反应的研究 : 1958 年,黄鸣龙等利用薯蓣皂为原料以七步合成了可的松,使我国的可的松合成跨进了世界先进行列。黄鸣龙对口服避孕药的结构研究和合成也作出了贡献。其中,甲地孕酮用口服避孕药不仅在我国是首创,在英国也被用作口服避孕药。
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坎尼扎罗 1826 年生于意大利西西里城一个警察局长之家, 1919 年去世。 中学时的坎尼扎罗便被认为是很有才能的学生,无论文学、数学还是历史均是成绩优异。 1841 年,坎尼扎罗进入巴勒莫大学医学系学习。他以求知欲和兴趣广泛而出众。他具有杰出的才干和顽强的性格,能深刻地掌握和理解课堂讲授的内容,因而深得教授们的赏识。他不仅听医学方面的课程,还常听文学和数学方面的课程。 19岁(即 1845 年)便在那不勒斯的代表大会上作了关于辨别运动神经和感觉神经方面的报告,受到与会代表的鼓励和鞭策,促使他一方面要从生物学的角度去研究,另一方面又要从化学方面去探索。
康尼查罗( S. Cannizzaro )
1845 年秋,坎尼扎罗前往比萨,并在著名实验家上皮利亚的实验室里当助手。在皮利亚的影响下,他深深爱上了化学这门学科。后来,他到法国巴黎,在舍夫勒实验室从事科研。 1850 年,他发表了关于氨基氰的论文,次年又发表了关于氨基氰受热后发生转化的论文。 不久,他便返回意大利的亚历山大里亚工业学院进行科学研究。有机合成的新发展,有机化学领域中一个个接踵而来的新发现,引起了他对研究苯甲醛及其特征反应的兴趣。他发现,把苯甲醛与碳酸钾一起加热时,苯甲醛特有的苦杏仁气味很快消失。产物与原来的苯甲醛完全不同,甚至气味也变得好闻了。他对反应混合物进行定量分析,先把反应混合物分成一个个组分,然后,再测定每种组分的含量。几天后,竟得几乎意料之外的结果:
在反应过程中,碳酸钾的量没有改变,即碳酸钾只起催化剂的作用。再进一步分析得知产物中既有苯甲酸,又有苯甲醇。 1853 年,坎尼扎罗公布了他的研究成果,人们把能生成这类产物的反应称为 Cannissaro 反应。 1855 年, 39岁的坎尼扎罗在热亚大学获得教授的职位。其后,他与贝塔尼等一起完成了对苯甲醇衍生物的研究–从苄醇制苄氯,又将苄氯转变成苯乙酸。从此,他一直注意化学的基本理论问题,并写成了 " 化学哲学发展纲要 " 的论文。该论文引起了全世界科学家的重视,因为他用新的观点说明了什么是原子、分子、原子量和分子量。为此,他被特邀参加了 1860 年国际化学家代表大会并发表了独特的见解,他的思想对化学领域中的原子 - 分子学说的发展产生了决定性影响,得到与会代表的赞同,从此,坎尼扎罗名声大噪。
坎尼扎罗毕生息于科学。由于他在化学上的杰出贡献, 1862年当选为伦敦化学学会名誉会员, 1873 年他做了纪念法拉弟的演讲并被推举为德国化学学会名誉会员。 1891 年,获得科佩尔奖章。
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加特曼出生于德国的哥斯他 (Gostar) ,最初在海德尔堡学习化学,后来转到柏林学习,得博士学位,他发现了不少有机合成方法,并以他的名字而命名反应。例如: 加特曼甲酰化制备醛( 1898 ); 加特曼 - 科克甲酰化制备醛( 1897 ); 加特曼 -斯基培吡啶的合成( 1916 ); 加特曼重氮基取代作用( 1890 )。
加特曼 (Ludwing Gattermann,1860--1921 ,德国化学家 )