2. VITAMINS
Besides Oxygen,Water,Fat,carbohydrates and salts,some
natural organic compounds are also necessary for the growth
of our body
Although,they are very important for our body These organic
compounds are known as vitamins
In 1911,the scientist “Funk” found that there are some
compounds present in our foods which protect us from
diseases like berry-berry,scurvy
That means in the absence of these compounds in our foods
,we may suffer from such diseases
3. According to “funk”,they are organic compounds
containing nitrogen element.He called them the
“vitamines”[vital-amines]
But,it was found there after that it is not necessary that
all these compounds should contain nitrogen atom.
Hence , the correction was made in their common name
and the new name “vitamins” was given
“vitamins” are the organic compounds which are
required in a very small amount by a living organism and
are necessary for the nourishment and growth of the
animals
4. CLASSIFICATION OF VITAMINS
Presently , there are about 25 vitamins.
They can be classified and some of them can also
be synthesised.
They are classified into two groups according to
their solubility in water and fats.
1. Water soluble vitamins
2. Fat soluble vitamins
5. 1. Water soluble vitamins
This class consists of vitamin-B[which includes Thiamine ,
Reboflavin , Pyridoxin , Nicotinic acid , Biotin and Folic acid]
and vitamin-c
2. Fat soluble vitamins
This class consists of vitamin-A , vitamin-B , vitamin-E and
vitamins-k
However , vitamin-H is an exception it is soluble in water as
well as in fats
6. NOMENCLATURS OF VITAMINS
Vitamins are desingnated by alphabets like
A,B,C,D,E,ets …… in order of their discovery some
vitamins do not exist in a pure form but in the form
of mixed compound.
Ex:-Vitamins-B complex :-This vitamins is a mixture
of B1,B2,B6,H,…..etc
7. VITAMIN-A1 OR RETINOL
Vitamin-A1 is a Fat soluble vitamin.
This vitamin is also known as Retinol.
Which is found present in the liver and blood of fish
CH2OH
8. It is also found present in carrot , green vegetable ,
sweet potatoes , tomatoes etc in form of carotenes
,which are easily converted into vitamin-A1.
Vitamin-A1 was isolated as a crystalline solid.
Its melting point is 63*-64*C.
It is optically active , sensitive to light and air , but it is
resistant to heat.
It can be destroyed by uv light.
9. Its deficiency in animal may cause night blindness
but a prolonged deficiency of this may lead to
hardening of conjactive and melting of cornea
which is termed as “Xerophthalmia” and may lead
to complete blindness in some cases.
Its deficiency also produced dryness of skin and
hair.
10. EVIDENCES TO PROVE THE
STRUCTURE
It’s molecular formula is :- C20H30O
Presence of 1*- alcoholic group:-
Vitamin – A1 forms an ester with P-nitro benzoic acid ,
indicating the presence of hydroxyl group in Vitamin-A1
Which was shown to be alcoholic in nature by Uv
spectra
11. Oxidation of Retinol gives Retinaldehyde having same
of carbon atoms .
This fact also lead to the conformation that an oxygen
atom is present as 1*- alcoholic group.
Presence of Five double bond:-
Vitamin-A1 an catalytic Reduction gives perhydro
retinal.
12. During the above reaction 5 mole of hydrogen are used up,
which confirm the presence of five double bonds in Retinol.
This reaction indicates the presence of 5 double bonds in
vitamin-A1.
Reduction
pt or Al/Hg +5H2
C20H30O
C20H40O
Per-hydro retinol
13. The formula of per-hydro retinol is C20H40O,So we can
say that the formula of parent hydrocabon will be C20H40
, which corresponds to the general formula CnH2n, for
compound having one ring.
Vitamin-A1 or Retinol also give an addition product with
2 mole of malic anhydride.
This reatcion indicates that vitamin-A1 contains four
ethylinic double bonds in the side chain.
14. This fact also confirm by the uv spectra.
Presence of B-ionone ring:-
C20H30O Ozonolysis
O3
COOH
COCH3
Ozonolysis
O
Vitamin-A1
Geronic acid
B-ionone
15. Vitamin-A1 an ozanolysis gives geronic acid.
The resultant acid is also obtained by the
ozanolysis of B-ionone.
This fact the presence of B-ionone residue in
Vitamin-A1.
16. Presence of three group
CH3
C
C20H30O
Oxidation
alk.KMnO4
Oxidation
hot cromic acid
Cro3
2 CH3COOH
3 CH3COOH
Acetic acid
Acetic acid
Vitamin-A1
17. Vitamin-A1 on oxidation with alkaline KMno4 at
high temp* give 2 mole of acetic acid.
Therefore, side chain of vitamin-A1 contanis two
group.
Vitami-A1 an oxidation with hot cromic acid give 3
moles of acetic acid, indicating the presence of
three group in Vitamin-A1
,which are in form of
CH3
C
CH3
C
CH3
CC
18. Presence of Isoprene unit:-
Most of the carotenoids contains isoprene units in
side chain, so we can say that Vitamin-A1 also
contains isoprene units in its side chain.
CH
CH3
CH2CH C
19. From the all arguments , we can say that vitamin-
A1 contains half of the B-carotene structure.
CH3 CH3
CH CH
CH CH
CH3
CH3
B-carotene
20. Number of isoprene units:-
Viamin-A1 an reaction with alcoholic HCl, yields an
anhydro compound (A) which an dehydrogenation
with seleniam yield 1,6-dimethyl naphthalene
