Альдегиды

1. Aldehydes and Ketones.

2. Oxo- group or
Carbonyl group
2
Aldehydes and ketones are compounds which
include oxo- group or carbonyl group.
.

3. 3
Aldehyde Ketone

4. 4

5. CH2
CH CHO CCl3
CHO
CH3
CH3
CH3
CH3
CH3
CHO
Acrolein Chloral Retinal
5

6. Propanone
Butanone
Pentanone-3
Pentanone-2
Butenone
6
CH3
C
O
CH3
CH3
C
O
CH2
CH3
CH2 C
O
CH2 CH3CH3
CH3
C
O
CH2
CH2
CH3
CH3
C
O
CH CH2

7. Structural Isomerism.
Oxo-group position (only for ketones)
Carbon Chain Isomerism
7
CH2 C
O
CH2 CH3CH3CH3
C
O
CH2
CH2
CH3
Pentanone-2 Pentanon-3
CH3 C
O
CH2 CH2 CH3
CH3
C
O
CH CH3
CH3
Pentanone-2 3-methylbutanone

8. Interclass Isomerism (Metamerism)
8
CH2 C
O
H
CH3CH3
C
O
CH3
Propanone Propanal

9. Structure
9
C
O....
C
O....
..
+
_
Propanone Ethanal

10. С О
δ+ δ-
Chemical Properties.
Addition to carbon - hetero double bonds (AN)
These bond is polar (have a large difference in electronegativity between
the two atoms) consequently carbon carries a partial positive charge. This
makes this atom the primary target for the nucleophile.

11. Nucleophilic Addition (AN)
δ+ δ-
Aldehyde or
ketone
slow
Nu─
Intermediate
product
fast
Product
Nu– C –OC = O Nu– C –OH
: ‒ H+
As Nu-agents can be: CN−
, H2O:, R−OH, :NH3
(:NH2R, :NHR2, :NR3) etc.

12. Decreasing of AN reactivity :
H–C > CH3–C > CH3–C– CH3 >
O
O
H
O
H
CH3–C– C6H5 > C6H5–C– C6H5
O O

13. Formalin solution
O
OH
OH
H– C –HH– C –H + HOH
..
δ+
OH
OH
ChloralhydrateChloral
δ-
O
H
C + H2
O CI3
C –C –HCI3
C
1. Addition of Water(hydration)

14. 2. Alcohols addition
Aldehyde Alcohol Hemyacetal Acetal
δ+
δ-
R′
OH
R– C –H R– C –HR –OH′
OR′
OR′
OR′
OH
R –C +
O
H
..

15. 15
CH3
C
O
H
+ C2
H5
OH CH3
C
O H
H
OC2
H5
Aldehyde Alcohol Hemyacetal

16. 3. Addition of sodium hydrosulphite:
δ-
O
OH
R–C +
O
CH3
δ+
:S –O – Na+
OH
OCH3
R– C – S–O– Na+
O

17. 4. Addition of HCN
17
+ C O
CH3
CH3
C
CH3
CH3
O HNCHCN
NaOH
Cyanohydrin
C O
CH3
CH3
N C: N C C
CH3
CH3
O
H
+
N C C
CH3
CH3
OH
Cyanid-ion Acetone Acetone
Cyanhydrin

18. ─ C – N–X
X = H, R, OH, NH2 etc.
δ+ δ- ‒H2O
Н
Н OH H
С = О + :N–X
Shiff’s Base
(if X = R,H)
– C = N – X
H+
··δ+ δ-
С = N–X + H2OС = O + H2N–X
5.

19. Addition-Elemination Reactions (AN-E)
R2C = O
H2N OH‒
hydroxylamine
R2C=N-OH
oxime
H2N NH─ 2
hydrosine
R2C=N-NH2
hydrozone
H2N NH C‒ ‒ 6H5
phenylhydrosine
H2N-NH-C-NH2
hemikarbaside
R2C=N-NHC6H5
phenylhydrosone
R2C=N-NH-C-NH2
hemikarbasone
Ammonium Derivatives Addition
··
·· ··
·· ··
ОO

20. 6. Aldol Condensation
20
CH3
C
O
H
CH3
C
O
H
+
OH-/H+
CH2 C
O
H
CH3 CH
OH
ethanal 3-hydroxybutanal (aldol)

21. Aldehydes without α-hydrogen are not undergo
aldol condensation
CH3
CH3
H
O
CH3– C–C
O
H
C

22. 22
OH CH2
O CH2
O CH2
O CH2
O CH2
OHn
a) Paraform- is the product of formaldehyde polymerisation
7. Aldehydes Polymerisation
CH
H
O
CH
H
O
CH
H
O
CH
H
O
CH
H
O
CH
H
O
C
H
H C C
OH OH
C
H
C
OH
C
O
H
OHOH
H H H
Ba(OH)2
b) Butlerov’s reaction (1861y) - first example of carbohydrate
obtaining.

23. 8. Red-Ox Reactions
a) Silver Mirrow Reaction (Tollen’s reaction)
23
CH3
C
O
H
CH3
C
O
OH
Ag(NH3
)2
OH
-Ag
Ethanal Ethanoic acid

24. 24
b) Oxidation with Сu(OH)2
Ethanal Ethanoic acid

25. СH3-CH2-C-CH3 2CH3COOH
25
Vargner's rule
Oxidation of asymmetric ketones go in a such a way that
oxo-group decomposed with the smallest radical
=
O
[O]
c) Ketone’s oxidation goes under harder than
aldehydes conditions with the chemical bond break.

26. d) Reduction
R–CH2–OH
Aldehyde Primary alkohol
R– C
H
O
Ketone Secondary Alcohol
R– C R– CH –R′
Li[AlH4]
OHR′
O
Li[AlH4]

27. e) The Cannizzaro reaction, named after its discoverer
Stanislao Cannizzaro, is a chemical reaction that involves the base-
induced disproportionation of an aldehyde lacking a
hydrogen atom in the alpha position. Cannizzaro first
accomplished this transformation in 1853, when he obtained
benzyl alcohol and benzoic acid from the treatment of
benzaldehyde with a base.
27
C
OH
+
C
OH
+ NaOH
CH
H
OH
+
C
O O Na
+
+1 +1
-1 +3
Benzaldehyde Benzyl Benzoic
Alkohol Acid Salt

28. 9. Carbonyl Compounds EN-OLisation
28
C
O
C
H
C
OH
C
Keto-form En-Ol-form
Iodoform Reaction
R C
O
CH3
I2, OH-
R C
O
O + CHI3
Acidic anion Iodoform