Derivative
Preparation
Dr. Anand Chintakrindi
Qualitative Analysis of
Organic Compound
• Preliminary Evaluation
• Organoleptic evaluation (color and odor)
• Solubility test
• Ignition test
• Unsaturation test
• Detection of Elements
• Detection of Functional Group
• Determination of Physical constants
• Preparation of Derivative
What is a derivative?
• A derivative is a compound that can be imagined to arise
or actually be synthesized from a parent compound by
replacement of one atom with another atom or group of
atoms.
Why is derivative preparation
required?
• To distinguish between similar compounds having similar
physical constants
p-toluidine (m.p. 44 °C)
1-napthylamine (m.p. 50 °C)
• Acetyl derivative prepared by acetylation
4-acetamidotoluene
(m.p. 148 °C)
1-acetamidonaphthalene
(m.p. 189 °C)
Which derivative to be prepared?
• Depends on the class of the compound
Acids
Diacids
Phenols and Amines
• Amide/Anilide/Ester
• Anhydrides
• Bromo/Benzoyl/Acetyl
Aldehydes and Ketones
• Phenyl hydrazone/Semicarbazone/Oxime
Esters/Amides/Anilides
• Hydrolysis product
Nitro hydrocarbons
• Amines
Hydrocarbons
• Nitro/Picrate
Carbohydrates
• Osazone
Requirements of a derivative
Easily Prepared
Good Yield
Possibly solid
Melting point should be
substantially different
How to prepare derivative?
• Amide Derivative
Shake 0.5 g
compd.
(acid) with
1.5 ml of
PCl5 till
vigorous
reaction
ceases
Warm the
solution
gently and
cool it
Add
cautiously
10 ml c.NH3
soln.
Filter off the
ppt (amide)
formed and
dry it
How to prepare derivative?
• Anhydride derivative
Take 1 g
compd.
(diacid) in
porcelain
dish
Keep a
funnel in
inverted
over dish
and loosely
plug the
stem of
funnel with
cotton
Heat the
dish on a
preheated
sand bath.
Collect the
anhydride
that
sublimes
and deposits
on inner
surface of
funnel
How to prepare derivative?
• Bromo derivative
Transfer 1
gm of the
compound
(phenol) into
a beaker and
dissolve in 3
mL of
methanol
Then add Br2
in acetic acid
until red
color of Br2
is persistent.
Keep aside
for 5-10
mins.
Add ice cold
water to the
mixture and
filter the
solid (bromo
derivative)
separated
out
How to prepare derivative?
• Acetyl derivative
Transfer 1mL
of the
compd.
(amine) into
a dry
conicalflask
add 3mL of
acetic
anhydride,
3mL of
glacial acetic
acid and
heat on a
water bath
for 10 mins
Transfer the
reaction
mixture into
a beaker
containing
cold water.
Filter the
solid acetyl
derivative
that
separates
out
How to prepare derivative?
• Hydrolysis derivative
Transfer 1gm
of compd.
(amide) into a
conical flask,
add 15mL of
20% NaOH
solution
heat it on a
Bunsen
burner till
the mixture
boils.
Cool the
reaction
mixture and
neutralize
with conc.
HCl.
A white ppt.
of carboxylic
acid
separates
out
How to prepare derivative?
• Nitro derivative
To 1mL of
hydrocarbon
add a mixture
of 2 mL of
conc.HNO3 &
4 mL of
conc.H2SO4
heat the
mixture on
water bath
for 20min
transfer the
mixture into
a beaker
containing
cold water
A yellow
ppt. of nitro
derivative
separates
out
How to prepare derivative?
• Osazone derivative
Dissolve 1gm
of
carbohydrate
in 5mL of
water
add 3mL of
glacial acetic
acid and
5mL phenyl
hydrazine
heat on
water bath
for 15min.
An yellow
crystalline
phenyl
osazone
separates
out.
Remember…
Safety First!
A spill, a slip, a hospital trip