Guided By: Submitted By: Ms. Aswathy Shaji (Guest Lecturer) Ansa MathewDepartment of Chemistry B.Sc. ChemistryMar Thoma College for Women Mar Thoma College for WomenPerumbavoor Perumbavoor

PREPARATION OF PHENYTOIN FROM BENZIL

CONTENTSOBJECTI

VEINTRODUCTION

PHENYTOIN

MATERIALS AND

METHODS

PREPARATIONS

RESULT AND DISCUSSION

CONCLUSION

OBJECTIVETo prepare Benzil by the oxidation of Benzoin.To prepare the anti-convulsant drug

‘Phenytoin’ from Benzil.Characterization of Benzil and Phenytoin by

their IR spectra.

INTRODUCTION DRUG It is a chemical substance used to treat, cure, prevent, diagnose a disease

or promote well-being.

ANTICONVULSANTS OR ANTIEPILEPTIC DRUGS (AEDs) Drugs used in the treatment of convulsive disorders like epileptic seizures. Provide symptomatic treatment only.

MODE OF ACTION Depress the CNS Non-specific Centrally acting Block sodium or calcium channels and reduce the release of excitatory

glutamate at high frequencies.

EXAMPLES OF AEDs Bromide- first anticonvulsant drug Phenobarbital Carbamazepine Phenytoin Valproic acid

PHENYTOINAEDUses Prevention of tonic- clonic seizures. Acute treatment of generalized status epilepticusMode of administration Intravenously By mouthMode of action Primary site of action appears to be the motor cortex,

where the spreading of seizure activity is inhibited. Phenytoin binds preferentially to the inactive form of the sodium channel.

Dosage of phenytoin Depends on blood serum levels i.e., between

10µg/mL and 20µg/mL. After the initial dose has been prescribed,

plasma levels should be determined and the dosage adjusted if necessary to obtain a level in the therapeutic range.

Excretion Most of the drug is excreted in the bile as

inactive metabolites which are then reabsorbed from the intestinal tract and excreted through the urine.

Common side effects

Nausea Stomach pain and loss of appetite Poor co-ordination Increased hair growth Enlargement of the gums Sleepiness Liver problems Bone marrow suppression Low blood pressure Toxic epidermal necrolysis

MATERIALS AND METHODSMATERIALS

1. Benzoin2. Conc.HNO3

3. Urea4. Ethanol

5. Dil.HCl6. Sodium Hydroxide

Methods

Infrared Spectroscopy- Spectroscopy that deals with the infrared region of the electromagnetic spectrum.

The instrument used is called infrared spectrometer or spectrophotometer.

A basic IR spectrum is essentially a graph of infrared light absorbance on the vertical axis vs. frequency or wavelength on the horizontal axis.

PREPARATION OF BENZIL

3g of Benzoin and 5mL of

conc.HNO3 are heated on a

water bath with a water

condenser , the flask being

subjected to occasional shaking.

Nitrous fumes are evolved and

crystals of Benzoin are converted to

yellow oil which after 2 hours of heating is free

from unchanged

Benzoin

The contents of the flask are poured into

water and the yellow

crystalline deposit is

separated by filtration.

It is then washed with water and

recrystallised from alcohol.

PREPARATIONS

PREPARATION OF PHENYTOIN

In an RB flask, 1.5g of Benzil, 0.75g of

urea, 22mL of Ethanol and 4.5mL

of 30% aqueous Sodium

Hydroxide are mixed.

The mixture is then boiled

gently for 2 hours on a water bath

After 2 hours, the reaction

mixture is cooled and

40mL of water is

added and the solution is filtered to remove the sparingly

soluble side product

The filtrate is then

acidified with 10mL of dil. HCl .

The product formed is filtered,

washed with water and kept for drying

RESULT AND DISCUSSIONIR ANALYSIS

IR Spectrum of Benzil

IR Spectrum Analysis Of Benzil

Benzil is synthesized by the oxidation of Benzoin.

The stretching frequency of

the free carbonyl group in the Benzil is

around 1700cm-1 .

A sharp band is obtained at

1600cm-1 . This is the characteristic stretching band

of Carbon-Carbon double bond.

The band appeared at

~3000cm-1 can be conveniently assigned to the aromatic C-H

stretching.

Structure Of Benzil

IR Spectrum Of Phenytoin

On comparison of the spectrum of phenytoin with that of Benzil, it is found that there are a few

noticeable changes between the two spectrums.

A new band has been occurred in the region 3400-

3100cm-1 This band corresponds to N-H

stretching. The broad character of the band is due to

H-bonding.

The band appeared at ~3000cm -1

corresponds to aromatic C-H

stretching.

The C=O stretching

vibrations can be seen around

the region corresponding to ~1700cm-1 .

The band appeared in between the

region 1400cm-1. and 1600 cm-1 gives the C-C

stretching vibrations of

aromatic ring.

Structure Of Phenytoin

Due to the small changes that happened in the spectrum of phenytoin when compared with that of Benzil, we can say that the structural similarity between phenytoin and Benzil is not much.

In phenytoin, in addition to two Benzene ring, the formation of a five member ring containing two C=O and the two N-H groups occurs.

CONCLUSION

In this present work, we prepared Benzil by the oxidation of

benzoin.

From Benzil, a major

anticonvulsant or an antiepileptic

drug named Phenytoin was

also synthesized.

Both the Benzil and Phenytoin

were characterized

by their IR spectra.

The difference in the spectral data indicates the change in the structures

of the two compounds.

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