A
PRESENTATION
ON
SEDATIVES & HYPNOTICS
Course Name: Medicinal Chemistry – I (Theory) [BP402T]
YOGESH MATTA
Assistant Professor, School of Pharmacy
Suresh Gyan Vihar University, Jaipur

LEARNING OBJECTIVES:
 The main objective is to impart fundamental knowledge on the structure, chemistry &
therapeutic values of drugs.
 The course emphasizes on Structure Activity Relationship of drugs.
 The course also include importance of structure & IUPAC name of various drugs.
 One of the most important objective of this course is to understand synthesis of some
important drugs under each category.
COURSE LEARNING OUTCOME:
Upon completion of the course, the student shall be able to
 Understand the chemistry of drugs with respect to their pharmacological applications.
 Understand the structure, IUPAC name & therapeutic values of various drugs.
 Know the SAR of different class of drugs that provides relationship between parent
drug & synthesized drug.
 Write the chemical synthesis of some important drugs.

CONTENTS
1. INTRODUCTION
2. CLASSIFICATION OF DRUGS
3. STRUCTURE
4. STRUCTURE ACTIVITY RELATIONSHIP OF DRUGS
5. SYNTHESIS
6. APPLICATIONS
7. QUIZ QUESTIONS
8. REFERENCES

SEDATIVES HYPNOTICS
 Drugs that reduce excitement, calms
the patient without inducing sleep.
 Drugs that reduce activity, decrease
excitement by inducing sleep resembling
to natural or normal sleep.
 Sedatives in therapeutic doses are
anxiolytic agents by producing mild
depression of CNS.
 Hypnotics are used for initiation and /
or maintenance of sleep by depressing
CNS.
 Most sedatives in larger doses produce
hypnosis.
 Hypnotics in higher doses produce
general anaesthesia.
 Delayed onset of action (slow acting)
and longer duration of action.
 Quicker onset of action (faster acting)
& have shorter duration of action.
 Site of action is on the limbic system
which regulates thought & mental
function.
 Site of action is on the midbrain and
ascending RAS which maintain
wakefulness.

CHEMICAL CLASSIFICATION
1. BENZODIAZEPINES 2. BARBITURATES 3. MISCELLANEOUS
COMPOUNDS
 Chlordiazepoxide  Barbital  Glutethmide
 Diazepam  Phenobarbital  Meprobomate
 Oxazepam  Mephobarbital  Ethchlorvynol
 Chlorazepate  Amobarbital  Triclofos sodium
 Lorazepam  Butabarbital  Paraldehyde
 Alprazolam  Pentobarbital
 Zolpidem  Secobarbital

N
N
NH
N
H
O
O
O
Barbituric acid
N
N
+
NH
OH
Cl
Chlordiazepoxide
N
N
Cl
O
Diazepam
N
N
Cl
O
OH
Oxazepam
N
N
Cl
O
O
OH
Chlorazepate
1,4-Benzodiazepine

N
N
Cl
O
OH
Cl
Lorazepam
NH
N
H
O
O
O
Barbital
NH
N
H
O
O
O
Phenobarbital
NH
N O
O
O
Mephobarbital Amobarbital
NH
N
H
O
O
O
Butabarbital
NH
N
H
O
O
O

STRUCTURE ACTIVITY RELATIONSHIP (SAR) OF BENZODIAZEPINES
N
N
R
R
1
R
2
R
3
R
2
The presence of electron attracting substituents or groups at C-7 position i.e R is required
for the optimal activity and more electron attracting substituents leads to effectiveness of
drug. (fluoro, chloro, bromo, nitro etc.)
For example: Diazepam, Chlordiazepoxide.
 The positions C-6, C-8 & C-9 should remain unsubstituted for optimal activity.

 Phenyl ring substitution at C-5 promotes activity. If the phenyl ring is substituted with
electron attracting groups at C-2 i.e R2, the activity will increase more.
For example: Lorazepam.
On the other hand, the substitution at C-3, C-4 & C-5 position will decrease the activity
greatly.
N
N
Cl
O
OH
Cl
Saturation of the N-4 & C-5 double bond or shift of it between the C-3 & N-4 will
decrease the activity.
Alkyl substitution at C-3 i.e R3 will decrease the activity but the presence of hydroxyl
group will enhance the activity.
For example: Oxazepam. N
N
Cl
O
OH

SYNTHESIS
Barbital
NH
N
H
O
O
O
5,5-diethyl-1,3-diazinane-2,4,6-trione
O O
O O
diethyl diethylpropanedioate
N
H2
N
H2
O
urea
+
NH
N
H
O
O
O
Barbital
-2C2H5OH

THERAPEUTIC USES
Insomnia
For example: Diazepam, Pentobarbital etc.
 Anxiety disorders
For example: Oxazepam, Amobarbital etc.
 Surgical anaesthesia
For example: Thiopental sodium, Methohexital sodium etc.
 Epilepsy & seizure states
For example: Phenobarbital, Mephobarbital, Secobarbital etc.
 Neuromuscular disorders
For example: Diazepam.

Quiz -1
Which of the following drug is an example of benzodiazepines?
(a) Barbital (b) Phenobarbital (c) Secobarbital (d) Diazepam
Quiz -2
Which of the following drug is an example of barbiturates?
(a) Oxazepam (b) Phenobarbital (c) Chlordiazepoxide (d) Diazepam
Quiz -3
Which of the following drug is a derivative of barbituric acid?
(a) Lorazepam (b) Mephobarbital (c) Chlordiazepoxide (d) Alprazolam
Quiz -4
Diazepam is mainly used in the treatment of convulsions & seizure state.
(a) True (b) False
Quiz -5
Which of the following drug is classified under miscellaneous category?
(a) Zolpidem (b) Pentobarbital (c) Chlorazepate (d) Meprobomate

REFERENCES
1. Alagarsamy V; Textbook of Medicinal Chemistry, Vol-I, Page no-88.
2. Pandeya S.N; Textbook of Medicinal & Organic Chemistry, Page no-124.
3. Singh Harkishan, Kapoor V.K; A Textbook of Medicinal & Organic Chemistry,
Page no-148.

THANK YOU