The document discusses psychoactive drugs and the synthesis of barbiturates and phenobarbital. It defines psychoactive drugs as chemicals that alter mood, behavior, and perceptions. It describes the four main types - stimulants, depressants, narcotics, and hallucinogens. It then focuses on barbiturates, describing their synthesis, mechanism of action by enhancing the GABA neurotransmitter, and uses including epilepsy treatment. Finally, it discusses phenobarbital as a long-acting barbiturate used for seizures, its synthesis, mechanism of action, uses, and disadvantages like withdrawal risks.

1. GOVERNMENT INSTITUTE OF SCIENCE
DEPARTMENT OF CHEMISTRY
SEMINAR ON
PSYCHOACTIVE DRUG
AND
SYNTHESIS OF BARBITURATE AND
PHENOBARBITAL
PRESENTED BY-
KIRAN A. BARBATKAR
M.SC. II SEMESTER III

2. WHAT ARE PSYCHOACTIVE DRUG…..
 A chemical substance that alters sensory perceptions , moods,
thinking and behavior.
 Impacts on neurotransmitter function.
 Neurotransmitter are the chemical signals that affect how happy ,
thirsty , anxious , scared , or tired you are. Eg., dopamine , GABA ,
noradrenalin etc.
 There are four general types of psychoactive drugs-
1. Stimulants
2. Depressant
3. Narcotics
4. Hallucinogens
 Example of common psychoactive drugs:
caffeine, cocaine , cannabis , ephedrine etc.

3. CLASSIFICATION OF PSYCHOACTIVE DRUGS
Antipsychotic Antianxiety Psychotomimetics
useful for anxiety
and phobic states
Antidepressant
useful in phobic states,
obsessive compulsive
behavior ,minor and major
depressive illness and some
anxiety disorder
Antimaniac
useful in all
types of
psychosis,
Particularly
schizophrenia
known as ‘mood
stabilizer ’
Effective for mania
and to break cyclic
effective disorder
known as
‘hallucinogens’

4. STIMULANTS
 Range from nicotine and caffeine to cocaine and crystal
meth.
 Block the reuptake or reabsorption of neurotransmitter
e.g. ., serotonin and dopamine which can lead to
increased energy , panic and anxiety.
Think about how coffee and cigarette can make you
jittery….

5. DEPRESSANTS
 Increases the production of
neurotransmitter GABA ( gamma –
Aminobutyric acid ).
 Which decreases reaction in brain.
 Affects cognition impairing memory.
 Depressants like benzodiazepines help
GABA neurotransmitter bind to
receptors that receive the chemical
signals , leading to reduced nervous
system activity and inducing sleep.

6. NARCOTICS
 Administered as painkillers.
 Used recreationally to create a sense of
euphoria .
 They stimulate your endorphins , which are
neurotransmitter that naturally reduces
pain .
 e.g., morphine , heroine and codeine etc.

7. HALLUCINOGENS
 They trick the brain into seeing or hearing things
that aren't there actually .
 Warps a persons sense of time and space.
 These altered states of consciousness can lead to
paranoia and anxiety .
 Eg., includes LSD ( Lysergic acid diethylamide ) ,
mescaline and ecstasy.

8. CNS DEPRESSANTS
Sedative Hypnotic
Depressants which
reduce restlessness and
emotional tension
without producing sleep
Exert a calming effect
Compel the users to
sleep
Reduce emotional tension
and restlessness
Produce drowsiness

9. SEDATIVE - HYPNOTICS
Benzodiazepines Barbiturates Miscellaneous Agents
Short
action
Intermediate
action
Long action
Ultra action
Short action
Long action
Buspirone
Chloral
Hydrate
Zaleplan
Zolpidem
Phenobarbitone

10.  Derivatives of Barbituric acid or
malonylurea : combination of urea
and malonic acid .
 Depressants of the central nervous
system , impair or reduce activity of
the brain by acting as a Gamma
Amino Butyric Acid (GABA)
potentiaters.
 Produce alcohol like symptoms such
as ataxia (impaired motor control ),
dizziness and slow breathing and
heart rate.
BARBITURIC ACID
BARBITURATE

11.  It was first prepared by a German scientist
Adolf Von Baeyer in 1864 ,combining
urea from animal and malonic acid from
apples.
 It was used as sleeping acid ( hypnotic
only) from 1903-1950 . Since 1950 they
are popular drug in the UK.
 It was estimated that 27000 people died
from barbiturates overdose in the UK
between 1959-1974.
HISTORY
Adolf Von Baeyer
(1835-1917)

12. SYNTHESIS OF BARBITURATE
 Condensation reaction are generally used in the
preparation of barbiturates.
 These reactions may take place in acidic , alkaline or
neutral media.
 In alkaline medium : In an alkaline medium
condensation reactions involve malonic esters ,
cyanoacetic esters and malonic amides on one hand
and urea or thiourea on the other hand .

13. Where X= O or S
Pharmacokinetics :
 Barbiturates are well absorbed from the
gastrointestinal tract.
 They are widely distributed in the body .
 Barbiturate with low lipid solubility are significantly
excreted unchanged in urine .

14. MODE OF ACTION
 In sufficient concentration barbiturate changes the
permeability of the cell membrane , thus causes reduction in
excitability of the photosynaptic cell .
 Barbiturate appears to act on the central synaptic
transmission process of the reticular activating system, hence
cerebral cortex becomes deactivated.
 They are antidepolarizing blocking agents.
 The cerebral electrical activity of a normal man increases
with anxiety, or consumption of a CNS stimulants like caffeine
, LAD etc.
 Administration of the barbiturates in large doses has a
calming effect .

15.  Barbiturate potentiate the GABA- mediated Cl ion
conductance and also interact at the picrotoxin
binding site .

16. MECHANISM OF ACTION
 Barbiturates potentiate the effect of GABA at the
GABA-A receptor.
 The GABA-A receptor is a ligand gated ion channel
membrane receptor that allows for the flow of Cl
through the membrane in neurons .
 GABA is present in all portion of brain and it
inhibits all CNS neurons ,thus stabilizing resting
membrane potential to remain in a depolarized
state.
 This makes it an inhibitory neurotransmitter .

17.  Uses : except for phenobarbitone in epilepsy and
thiopentone in anesthesia barbiturates are rarely used
now. They are occasionally used as adjuvants in
psychosomatic disorders
Adverse effects :
 When repeatedly used in night ,they accumulate in the
body and may cause dependence , tolerance ,
impaired performance, mental confusion and traffic
accidents.
 In an occasional user , they produces excitement.
 Hangover is a common effect after the use of
barbiturate as hypnotic

18. PHENOBARBITAL
 It is a type of long acting barbiturates.
 Because the duration of action lasts for 6-10 hours.
 They are largely excreted by kidney.
 Phenobarbital is used in the treatment of all types of
seizures except absence seizures.
 It is no less effective at seizure control than phenytoin
.

19. MODE OF ACTION
 Through its action on GABA receptors, phenobarbital
increases flux of chloride ions into the neuron which
decreases excitability.
 Direct blockade of excitatory glutamate signaling is also
believed to contribute to the hypnotic/anticonvulsant
effect that is observed with the barbiturates

21. SYNTHESIS :

22. USES
 Phenobarbital is a commonly used agent in high purity
and dosage for lethal injection of "death row" criminals.
 Phenobarbital is used as a secondary agent to treat
newborns with neonatal abstinence syndrome, a
condition of withdrawal symptoms from exposure to
opioid drugs in utero.
 In massive doses, phenobarbital is prescribed to
terminally ill patients to allow them to end their life
through physician assisted suicide.

23. DISADVANTAGES :
 Side effects include a decreased level of
consciousness along with a decreased effort to
breathe.
 There is concern about both abuse and withdrawal
following long-term use . It may also increase the
risk of suicide.

24. REFERENCES :
 Medicinal chemistry by Ashutosh Kar.
 Medicinal chemistry by Chatwal.
 Medicinal chemistry by Alka Gupta .
 www.google.com
 www.sciencedaily.com
 www.slideshare.net
 https://en.wikipedia.org/wiki/Phenobarbital#Mechanism
_of_action
 https://images.slideplayer.com
 clinicalgate.com
 cdn.britannica.com