45

CHAPTER IV

46

CHAPTER IV

i. Characterization and biological activity of the carbanionic sigma

complex derived from 1-chloro-2,4-dinitrobenzene, pyrimidine-2,4,-6-

(1H,3H,5H)-trione and triethylamine.

Ethanolic solution of 1-chloro-2,4-dinitrobenzene (DNCB) shows wave length

of maximum absorption at 290 nm. When triethylamine is added to the mixture of

DNCB and pyrimidine-2,4,-6-(1H,3H,5H)-trione (barbituric acid) in ethanol, a dark

maroon red colour is obtained, from which maroon red coloured crystals have

been isolated. This maroon red colour product has been identified as carbanionic

sigma complex 26 [triethylammonium 2,4-dinitrophenylbarbiturate, systematic name:

triethylammonium 5-(2,4-dinitrophenyl-2,6-dioxo-1,2,3,6-tetrahydropyrimidin-4-

olate)].

N

H NO2

H H H

H

O

O

O

ON

HO O2N

H

N

OH

C N

NC

26b

O

O H

26a

HNO2

H H H

HO

O2N

O

O H N

H3CH2C

CH2CH3CH2CH3CH2CH3

H3CH2C

H3CH2C

CH2CH3CH2CH3CH2CH3

N

C

N

HH

NO2H

N

C

N

Complex 26 (barbiturate)

47

Structure of 26 has been confirmed from visible, IR, PMR, 13

C NMR, COSY, Mass

spectral studies and single crystal X-ray analysis. Elemental analysis and other

qualitative tests have also been performed to throw light on the proposed structure.

The physical data of complex 26 are presented in Table 1. Table 2 reflects the

wavelength of maximum absorption of complex 26 in various solvents of different

polarity. Some important IR spectral data of DNCB, barbituric acid and complex 26

are given in Table 3. PMR spectral data of DNCB, barbituric acid and complex 26

are summarized in Table 4. Figs. 1,2 and 3 are the IR spectra of DNCB, barbituric

acid and complex 26 respectively. Figs. 4,5 and 6 correspond to the PMR spectra of

DNCB, barbituric acid and complex 26. 13

C NMR spectra of DNCB, barbituric acid

and complex 26 are presented in Figs. 7,8 and 9 respectively. Figs 10 and 11 are the

proton-proton COSY and Mass spectrum of complex 26.

The isolated complex 26 is coloured because of the delocalization of charge

over a large area. Qualitative tests197

on complex 26 reveal the presence of nitrogen

atom, nitro groups and the absence of chlorine. In DNCB, a strong sharp absorption

band characteristic of C-Cl stretching mode has been observed at 732 cm-1

, which is

absent in the synthesized complex 26, clearly shows that during the formation of

complex 26, chlorine is removed from DNCB. Since upon the formation of the

complex, the aromatic nitro group is converted to one bearing partial negative charge,

the asymmetric and symmetric absorption frequencies are expected to decrease.17, 48

This has been observed in the present study also (Table 3). The broad band observed

between 2700 – 3400 cm-1

in complex 26 is characteristic of amine salt.198

In the

synthesised complex C=C stretching band appears at 1600 cm-1

. This may be

probably due to stretching of C=C band during delocalization.

In barbituric acid, N-H proton signal appears at 11.09 ppm. During the

formation of complex 26, the negative charge is delocalized over a large area upto the

keto functions nearer the N-H groups and hence the N-H protons are shielded to some

extent and show shift towards upfield. The adjacent ring protons of the nitro moiety

appear as double doublet in DNCB, whereas in the complex it has become a multiplet

supporting the delocalization of the negative charge.

48

Table 1

Physical Data of Complex 26

Data Complex 26

Molecular Formula C16H21N5O7

Molecular Weight 395

Physical State Maroon Red Crystalline Solid.

Stability Stable under ordinary conditions.

Decomposes if heated to high

temperatures.

Melting Point 535-537K (Decomposes at its melting

point).

Solubility Soluble in water (4g/l at 298K), insoluble

in ether.

pH (0.001M solution in water) 6.8

Toxicity (LD50) >1000mg/kg

Yield (pure crystals) 60%

Table 2

max and max of Complex 26 in solvents of different polarity

S.

No. Solvent

Concentration

of Complex 26

x 105M

max (nm)

max (mol

-1 l cm

-1)

1 dimethyl sulphoxide 0.50 480 70000

2 water 5.00 395 20000

3 ethanol 5.00 425 27000

4 2-butanol 4.63 435 24840

5 2-methyl-1-propanol 7.00 420 22530

6 methanol 5.00 420 19000

7 glycol 5.00 420 14800

8 1-propanol 5.00 420 11200

9 tert-butylalcohol 10.00 435 10000

10 benzyl alcohol 5.00 440 8400

11 2-butanone 5.00 460 31000

12 acetone 5.00 485 27800

13 acetophenone 0.25 475 10000

14 dioxan 10.00 380 3500

49

Table 3

IR spectral data

Group

1-Chloro 2,4-

dinitrobenzene

(cm-1

)

Barbituric acid

(cm-1

)

Complex 26

(cm-1

)

NO2 asym. str. 1545 (s,sh) - 1516 (m,b)

NO2 sym. str. 1351 (s,sh) - 1343 (s,sh)

C – Cl str. 732 (s,sh) - -

C = O str. - 1716 (s,sh) 1712 (s,sh)

C = C str. - - ~ 1600 (s,sh)

N – H str. - 3479, 3529 (s) 2700-3400 (s,b)

Table 4

PMR spectral data

Molecule Position of

absorption peaks Proton type

1-Chloro-2,4-

dinitrobenzene 8.76 (s,1H)

8.46 (d,1H)

7.92 (d,1H)

Ring proton of nitro moiety

Adjacent ring

protons of nitro moiety

Barbuturic acid 11.09 (s, 2H)

3.39 (s, 2H)

Two N – H protons

H2C – protons

Complex 26 9.66 (s, 2H)

8.36 (s, 1H)

8.15 to 8.25

(m, 2H)

1.15 (t, 9H)

3.08 (q, 6H)

Two N – H protons

Ring protons of nitro moiety

Adjacent ring protons of nitro moiety

–CH3 of HN (CH2CH3)3

–CH2 of HN (CH2CH3)3

50

51

52

Fig.3 IR spectrum of Complex 26

53

54

Fig.4a PMR spectrum of 1-chloro-2,4-dinitrobenzene

55

56

57

58

Fig.7 13

C NMR spectrum of 1-chloro-2,4-dinitrobenzene

59

60

61

Fig.10 Proton-proton COSY of Complex 26

62

Fig.11 Mass spectrum of Complex 26

63

Proton–proton COSY of complex 26 (Fig.10) reveals that 1H –

1H coupling has occurred

between the protons in the cation moiety. 13

C spectrum of barbituric acid exhibits two

signals at 151.7 ppm and 167.8 ppm due to the keto group carbon atoms. Six signals have

been observed in the 13

C spectrum of DNCB. Carbon atom bearing Cl appears at 133.6 ppm.

The synthesized complex 26 exhibits 11 signals in the 13

C spectrum. The absorption peaks at

8.6 ppm and 45.8 ppm are due to the carbon environments of CH3 and CH2 groups

respectively of triethylammonium ion. The absorption peak at 86.6 ppm is not noticed in

DNCB and barbituric acid but only in complex 26 may be due to the newly formed carbon

environment (C=C).199

In FABMS, base peak corresponds to triethylammonium cation (m/z

= 102) is found. Based on spectral observations, Scheme 4 has been proposed for the

formation of complex 26 from DNCB and barbituric acid in the presence of triethylamine.

The structure of complex 26 has been confirmed through single crystal X-ray

analysis.

Crystal data of complex 26

Empirical

formula

C6H16N+. C10H5N4O7

-

Formula weight 395.38

Radiation Mo K Wavelength 0.71073 Å

Volume 3689.20(17)Å3 Temperature 293 K

Crystal system,

space group

Monoclinic, C2/c

Z, Calculated

density

8, 1.424 mg m-3

Unit cell

dimensions

a = 29.7900 (8) Å,

Absorption

coefficient

0.113 mm-1

b = 10.4533 (3) Å, F(000) 1664

c = 11.9606 (3) Å, Crystal size 0.30 x 0.20 x 0.20 mm

alpha = 90.00°

Theta range for

data collection

1.38 to 24.93°

beta = 97.70° R factor 0.0396

gamma = 90.00° CCDC Number 721014

64

Selected bond lengths and bond angles of complex 26 are listed in Table 5. ORTEP view of

complex 26 is shown in Fig.12. The presence of the leaving group (chlorine atom) para

with respect to the nitro group of the starting molecule (1-chloro-2,4-dinitrobenzene)

facilitates the formation of complex 26 in the presence of barbituric acid and triethylamine.

Absence of chlorine atom, as indicated by the qualitative test on the synthesized barbiturate

has been supported by the crystallographic data. The title molecule is coloured maroon red

and it has been attributed to the delocalization of negative charge which has also been

substantiated by the bond angles and bond lengths of single crystal X-ray data of 2,4-

dinitrophenyl and barbiturate rings. The bond angles and bond lengths of barbiturate residue

of complex 26 are compatible with that of barbiturate ion 27200

evidencing the delocalization

of negative charge in the barbiturate.

C

N

C

N

C

C

H

O

HH

(1)

(2)

(3)

(4)

(5)

(6)

(2)

1.41Å1.25Å

117.6

1.39Å

125.2

1.37Å

123.6

115.11

117.0

119.9

1.35Å

121.3

1.23Å

125.7

117.1

1.39Å

117.6

1.22Å1.41Å(6)

(4)

O

O

27

Presence of double bond (delocalized) between C3 and C5 atoms fixes the

configuration of the molecule as depicted in Fig.12. The N5–H5…O2 hydrogen bond

between the asymmetric units is the main driving force for the orientation of the

triethylammonium cation (Fig.13). Two inversion related barbiturate anions interact through

a pair of N–H…O=C hydrogen bonds involving N1 – H1 atoms and carbonyl oxygen atom

(O1) forming a R22 (8) ring motif. The same ring motif is also due to a pair of N–H…O

hydrogen bonds involving N2 – H2 atoms and the carbonyl oxygen atom (O3). This motif

is one of the 24 most frequently observed bimolecular cyclic hydrogen – bonded motifs in

organic crystal structures.201

The hydrogen bonds (Table 6) observed in complex 26 are

mainly responsible for its stability. The high solubility of the complex in water (4g/cc at

65

298K) is due to the positively charged triethylammonium cation and negatively charged 2,4-

dinitrophenylbarbiturate anion of the asymmetric unit.

Anticonvulsant activity of complex 26

Complex 26 (barbiturate) is screened for anticonvulsant activity.202

The barbiturate

has been given one hour before the induction of Maximal Electro Shock (150mA / 0.2sec).

The current has been applied on the animals using the corneal electrodes. The barbiturate

shows activity even at low concentration (50mg/kg). The different stages of convulsions such

as tonic flexor, tonic extensor, clonus convulsion, stupor and recovery / death have been

examined. Reduction in extensor phase of convulsion has been noticed for the synthesized

barbiturate (Table 7). This implies that synthesized barbiturate of the present work may be

used as a drug for grand mal type of epilepsy.

Hypnotic activity of complex 26

Complex 26 induces hypnosis in albino mice (Table 8).

Acute toxicity study on complex 26

LD50 of the synthesized barbiturate has been examined as per OECD guidelines

(revised draft 423). The barbiturate falls under class 3 (LD50>1000mg/kg). The animals did

not show any signs of acute toxicity and behavioral changes (Table 9).

66

Scheme 4

Synthetic route of formation of Complex 26

eqn. 3

eqn. 2

NH

H

HNR3+

H

N Cl

O

O

OO

C

C

C N

N

H

O H

O H

O

1-Chloro-2,4-dinitrobenzene

O

O Cl

N

H

R3N

H

H

H

N

OO

O O

O

O

HO

H

C

C

C N

C

N

O

O

N

N

H

R3N

H

H

HHNR3Cl

O O

O

O Cl

N

N

H

R3N

H

H

H

O

NR3+O

HO

H

C

C

C N

N

H

O

O

HO

H

C

C

C N

N

H

(2nd molecule)

amine

Synthesized Barbiturate (Complex 26)

[R = CH2 - CH3]

N

N C

C

C

O + NR3

amine

H O

H

H H

OH

OH

O

N

N C

C

C

HNR3+

O

Barbituric acid

eqn. 1H

(1st molecule)

+

+

67

Table 5

Selected Bond Lengths and Bond Angles of Complex 26 (Å, °)

C1-O1 1.228(2) C5-C10 1.397(3)

C1-N1 1.357(2) C6-N3 1.471(2)

C1-N2 1.357(2) C6-C7 1.377(2)

C2-O2 1.248(2) C7-C8 1.373(3)

C2-N1 1.381(2) C8-C9 1.380(3)

C2-C3 1.412(2) C8-N4 1.464(2)

C3-C4 1.408(2) C9-C10 1.379(3)

C3-C5 1.466(2) N3-O4 1.217(2)

C4-O3 1.242(2) N3-O5 1.223(2)

C4-N2 1.396(2) N4-O6 1.212(2)

C5-C6 1.395(2) N4-O7 1.210(2)

O1-C1-N1 122.11(17)

N2-C4-C3 116.04(15)

O1-C1-N2 122.00 O6-N4-C8 118.64(19)

N1-C1-N2 115.45(16) O7-N4-O6 123.20(18)

C1-N1-C2 125.39

O7-N4-C8 118.14(19)

N1-C2-O2 118.42(15) C10-C5-C3 121.05(17)

N1-C2-C3 116.74(15) C3-C5-C6 122.95(16)

C1-N2-C4 125.53(16) C6-C5-C10 115.80(16)

O2-C2-C3 124.84(16) C7-C6-C5 123.46(16)

O4-N3-O5 123.88(17) C7-C6-N3 114.89(16)

C2-C3-C4 120.71(16) C5-C6-N3 121.64(15)

C4-C3-C5 121.58 (15) C8-C7-C6 117.81(17)

O4-N3-C6 118.73 C9-C8-C7 121.94(16)

O5-N3-C6 117.36(16) C7-C8-N4 117.74(18)

C2-C3-C5 117.63(15) C9-C8-N4 120.34(17)

N2-C4-O3 117.69(16) C10-C9-C8 118.50(17)

C3-C4-N2 116.00 C5-C10-C9 122.44(18)

O3-C4-C3 126.22(16)

68

Table 6

Hydrogen bond geometry (Å, °) of Complex 26

D-H…A d (D-H) d(H…A) d(D…A)

69

Fig. 13 Hydrogen bonding pattern and packing view of Complex 26

70

Table 7

Anticonvulsant activity of Complex 26 against MES

induced convulsion in Albino Rats

S.

No. Treatment

Time (sec) in various phases of convulsion

Flexor Extensor Clonus Stupor Recovery /

Death

1. Control

Normal Saline

(5ml/kg)

3.24

±

0.09

13.30

±

0.25

9.24

±

0.21

137.00

±

8.24

Recovered

2. Complex 26

(25mg/kg)

4.20

±

0.23

13.20

±

0.51

7.20

±

0.31

105.50

±

6.80

Recovered

3. Complex 26

(50mg/kg)

3.10

±

0.05

6.50

±

0.65

5.10

±

0.61

82.20

±

6.10

Recovered

4. Complex 26

(100mg/kg)

2.90

±

0.05

2.00

±

0.00

5.60

±

0.46

85.70

±

6.90

Recovered

5. Phenytoin

(standard)

(25mg/kg)

2.66

±

0.55

0.00

±

0.12

4.60

±

0.38

62.10

±

3.30

Recovered

Table 8

Hypnotic action of Complex 26

S.

No. Treatment

Dose

(mg/kg)

Time of

Admini-

stration

(mins)

(a)

Time of

loss of

reflex

(mins)

(b)

On set

of

action

(mins)

(b-a)

Time of

Recovery

(mins)

(c)

Duration

of action

(mins)

(c-b)

1 Control

Normal

saline

1 ml/kg

0 -- -- -- --

2 Complex 26 100

mg/kg 0

20.6 ±

4.14

20.6 ±

4.14

206.2 ±

2.10

185.6 ±

3.32

3 Phenobarbitone

Standard

20

mg/kg 0

16.4 ±

2.25

16.4 ±

2.25

257.9 ±

3.27

241.50 ±

5.90

71

Table 9

Data showing effect of Complex 26 on behavioural profiles of mice

Responses

Treatment

Score

(Normal Saline)

Score due to

Complex 28

Muscle Tone

Limp tone 4 4

Grip tone 4 4

Body tone 4 4

Abdominal tone 4 4

Reflexes

Pinna 4 4

Corneal 4 4

Writhing 0 0

Autonomic Profile

Urination 0 0

Salivation 0 0

Respiratory rate 4 4

Awareness

Alertness 0 0

Passivity 0 0

Aggression 0 0

Mood

Restlessness 0 0

Fearfulness 0 0

Touch response 4 4

Motor Activity

Pain response 4 4

Twitches 0 0

CNS excitation

Tremors 0 0

Convulsions 0 0

Body posture 4 4

Posture

Limb posture 4 4

72

ii. Characterization and biological activity of the carbanionic sigma

complex derived from 1-chloro-2,4-dinitrobenzene, pyrimidine-2,4,-6-

(1H,3H,5H)-trione and tri-n-butylamine

Orange red colour crystals have been isolated from the ethanolic solution of

DNCB, barbituric acid and tri-n-butylamine. Based on physical data (Table 10),

visible spectral data (Table 11), IR data (Table 12; Fig. 14), PMR data (Table 13,

Fig.15), 13

C NMR data (Fig. 16), COSY (Fig. 17), Mass (Fig. 18) and elemental

analysis data – found (calculated) 55.38 (55.11), H 6.53 (6.88), N 14.13 (14.61),

structure 28 has been assigned for the isolated molecule [tri-n-butylammonium 2,4-

dinitrophenylbarbiturate, systematic name: tri-n-butylammonium 5-(2,4-

dinitrophenyl-2,6-dioxo-1,2,3,6-tetrahydropyrimidin-4-olate)]. 13

C NMR spectrum of

complex 28 exhibits 13 signals The absorption peak at 86.69 ppm corresponds to

the newly developed C=C environment. In the mass spectrum base peak corresponds

to tri-n-butylammonium cation (m/z = 186) is found. Single crystal X-ray data

(Tables 14-16, Figs. 19,20) confirm the putative structure.

Crystal data of Complex 28

Molecular formula C22 H33 N5 O7

Formula weight 479

Temperature 293(2) K

Radiation MoK

Wavelength 0.71073 Å

Crystal system, space group Monoclinic, C2/c

Unit cell dimensions a = 10.2132(14)Å alpha = 90.00°

b = 14.7146(10)Å beta = 91.674(9)°

c = 34.200(3)Å gamma = 90.00°

Volume 5137.5(9) Å3

73

Z, Calculated density 4, 1.235 mg m-3

F(000) 2032

Theta range for data collection 2.58 to 65.00 deg.

Completeness to theta = 65.00 98.4 %

Final R indices [I >2sigma(I)] R1 = 0.1017, wR2 = 0.2869

R indices (all data) R1 = 0.1829, wR2 = 0.3554

Disorder is observed in the lengthy alkyl chain (C22 is disorder with an occupancy of

45%)

The synthesized barbiturate 28 also has anticonvulsant / hypnotic activities

(Table 17 & 18). The LD50 of barbiturate 28 is > 490 mg/kg. The animals did not

show any signs of acute toxicity and behavioural changes (Table 19). The synthesized

barbiturates of the present investigation (26 & 28) may probably be the potent drugs

in future for grand mal type convulsion because of their extraordinary stability, low

toxicity, high solubility in water and easy method of preparation.

H

O

N

H NO2

H H H

H

O

O

O

ON

HO O2N

HNO

C N

NC

28b

O H

28a

N

C

N

HH

NO2H

N

C

N

NHO

O

O2N

OH

HHH

NO2H

Complex 28 (barbiturate)

74

Table 10

Physical Data of Complex 28

Data Complex 28

Molecular Formula C22H33N5O7

Molecular Weight 479

Physical State Orange Red Crystalline Solid.

Stability Stable under ordinary conditions.

Decomposes if heated to high

temperatures.

Melting Point 521-523K (Decomposes at its

melting point).

Solubility Soluble in water (3.5g/l at 298K),

insoluble in ether.

pH (0.001M solution in water) 6.8

Toxicity >490mg/kg

Yield (pure crystals) 70%

Table 11

max and max of Complex 28 in solvents of different polarities

S.

No. Solvent

Concentration

of Complex 28

x 105M

max (nm)

max (mol

-1 l cm

-1)

1 dimethyl sulphoxide 1.16 465 76388

2 water 1.16 390 34300

3 ethanol 2.70 425 48000

4 methanol 3.80 425 22300

5 1-propanol 3.80 425 17842

6 tert-butylalcohol 3.80 420 19600

7 benzyl alcohol 5.80 400 7000

8 2-butanone 1.90 480 11670

9 acetone 0.78 470 12400

10 acetophenone 2.70 465 14814

11 1-butanol 1.55 380 15748

12 acetonitrile 2.70 450 21060

75

Table 12

IR spectral data

Group

1-Chloro 2,4-

dinitrobenzene

(cm-1

)

Barbituric acid

(cm-1

)

Complex 28

(cm-1

)

NO2 asym. str. 1545 (s,sh) - 1518(m,sh)

NO2 sym. str. 1351 (s,sh) - 1334 (s,sh)

C – Cl str. 732 (s,sh) - -

C = O str. - 1716 (s,sh) 1704(s,sh)

C = C str. - - 1594(s,sh)

N – H str. - 3479, 3529 (s) 2700-3200 (s,b)

Table 13

PMR spectral data

Molecule Position of absorption peaks Proton type

1-Chloro 2,4-

dinitrobenzene

8.76 (s,1H)

8.46 (d,1H)

7.92 (d,1H)

Ring proton of nitro moiety

Adjacent ring

protons of nitro moiety

Barbituric acid

11.09 (s, 2H)

3.39 (s, 2H)

Two N – H protons

–CH2 Protons

Complex 28 9.68 (s, 2H)

8.84 (b, 1H)

8.16 to 8.38 (m, 3H)

3.03 (blurred triplet, 6H)

1.56 (quintet, 6H)

1.31 (sextet, 6H)

0.90 (t, 9H)

N – H protons

HN – of H

N (CH2-CH2-CH2-CH3)3

Ring protons of nitro moiety

–CH2 attached to nitrogen atom of

HN (CH2-CH2-CH2-CH3)3

–CH2 flanked by two methylene

groups of HN (CH2-CH2-CH2-CH3)3

–CH2 nearer to -CH3 of HN

(CH2-CH2-CH2-CH3)3

–CH3 of HN (CH2-CH2-CH2-CH3)3

76

77

Fig.15 PMR spectrum of Complex 28

78

Fig.15a PMR spectrum of Complex 28

79

Fig.15b PMR spectrum of Complex 28

80

Fig.16 13

C NMR spectrum of Complex 28

81

Fig.17 Proton-proton COSY of Complex 28

82

Fig.17a Proton-proton COSY of Complex 28

83

Fig.18 Mass s spectrum of Complex 28

84

Table 14

Selected bond lengths (Å) of Complex 28

C(1)-C(6) 1.344(9) C(13)-C(14) 1.412(14)

C(1)-C(2) 1.381(10) C(13)-H(13A) 0.9700

C(1)-N(1) 1.473(8) C(13)-H(13B) 0.9700

C(2)-C(3) 1.392(8) C(14)-H(14A) 0.9600

C(2)-H(2) 0.9300 C(14)-H(14B) 0.9600

C(3)-C(4) 1.381(8) C(14)-H(14C) 0.9600

C(3)-N(2) 1.500(9) C(15)-C(16) 1.397(14)

C(4)-C(5) 1.412(9) C(15)-H(15A) 0.9700

C(4)-C(7) 1.466(7) C(15)-H(15B) 0.9700

C(5)-C(6) 1.374(8) C(16)-C(17) 1.393(14)

C(5)-H(5) 0.9300 C(16)-H(16A) 0.9700

C(6)-H(6) 0.9300 C(16)-H(16B) 0.9700

C(7)-C(8) 1.408(8) C(17)-C(18) 1.469(17)

C(7)-C(10) 1.416(7) C(17)-H(17A) 0.9700

C(8)-O(5) 1.263(6) C(17)-H(17B) 0.9700

C(8)-N(3) 1.369(6) C(18)-H(18A) 0.9600

C(9)-O(7) 1.229(6) C(18)-H(18B) 0.9600

C(9)-N(4) 1.357(7) C(18)-H(18C) 0.9600

C(9)-N(3) 1.359(6) C(19)-C(20) 1.402(9)

C(10)-O(6) 1.238(6) C(19)-H(19A) 0.9700

C(10)-N(4) 1.397(6) C(19)-H(19B) 0.9700

N(1)-O(1) 1.211(9) C(20)-C(21) 1.524(9)

N(1)-O(2) 1.252(10) C(20)-H(20A) 0.9700

N(2)-O(4) 1.190(6) C(20)-H(20B) 0.9700

N(2)-O(3) 1.221(7) C(21)-C(22) 1.501(10)

N(3)-H(3N) 0.895(10) C(21)-C(22') 1.508(10)

N(4)-H(4N) 0.897(10) C(22)-H(22A) 1.1086

N(5)-C(19) 1.449(10) C(22)-H(22B) 1.1121

N(5)-C(11) 1.454(10) C(22)-H(22C) 1.1116

N(5)-C(15) 1.457(12) C(22')-H(22D) 0.9666

N(5)-H(5A) 0.9100 C(22')-H(22E) 0.9667

C(11)-C(12) 1.352(14) C(22')-H(22F) 0.9669

C(11)-H(11A) 0.9700

C(11)-H(11B) 0.9700

C(12)-C(13) 1.460(12)

C(12)-H(12A) 0.9700

C(12)-H(12B) 0.9700

85

Table 15

Selected bond angles (°) of Complex 28

C(6)-C(1)-C(2) 120.9(6) C(9)-N(3)-C(8) 125.7(5)

C(6)-C(1)-N(1) 121.5(8) C(9)-N(3)-H(3N) 115(3)

C(2)-C(1)-N(1) 117.5(7) C(8)-N(3)-H(3N) 120(3)

C(1)-C(2)-C(3) 118.3(6) C(9)-N(4)-C(10) 125.7(4)

C(1)-C(2)-H(2) 120.8 C(9)-N(4)-H(4N) 115(4)

C(3)-C(2)-H(2) 120.9 C(10)-N(4)-H(4N) 119(4)

C(4)-C(3)-C(2) 122.9(7) C(19)-N(5)-C(11) 111.7(8)

C(4)-C(3)-N(2) 121.6(5) C(15)-C(16)-H(16B) 107.5

C(2)-C(3)-N(2) 115.4(6) H(16A)-C(16)-H(16B) 107.0

C(3)-C(4)-C(5) 115.5(5) C(16)-C(17)-C(18) 114.5(13)

C(3)-C(4)-C(7) 124.2(7) C(16)-C(17)-H(17A) 108.6

C(5)-C(4)-C(7) 120.1(5) C(18)-C(17)-H(17A) 108.6

C(6)-C(5)-C(4) 122.0(6) C(16)-C(17)-H(17B) 108.7

C(6)-C(5)-H(5) 119.0 C(18)-C(17)-H(17B) 108.7

C(4)-C(5)-H(5) 119.0 H(17A)-C(17)-H(17B) 107.6

C(1)-C(6)-C(5) 120.3(7) C(17)-C(18)-H(18A) 109.5

C(1)-C(6)-H(6) 119.9 C(17)-C(18)-H(18B) 109.5

C(5)-C(6)-H(6) 119.9 H(18A)-C(18)-H(18B) 109.5

C(8)-C(7)-C(10) 119.8(5) C(17)-C(18)-H(18C) 109.5

C(8)-C(7)-C(4) 119.7(4) H(18A)-C(18)-H(18C) 109.5

C(10)-C(7)-C(4) 120.3(5) H(18B)-C(18)-H(18C) 109.5

O(5)-C(8)-N(3) 118.1(5) C(20)-C(19)-N(5) 120.9(10)

O(5)-C(8)-C(7) 124.2(5) C(20)-C(19)-H(19A) 107.0

N(3)-C(8)-C(7) 117.7(4) N(5)-C(19)-H(19A) 107.1

O(7)-C(9)-N(4) 122.0(4) C(20)-C(19)-H(19B) 107.1

O(7)-C(9)-N(3) 123.0(5) N(5)-C(19)-H(19B) 107.1

N(4)-C(9)-N(3) 115.0(4) H(19A)-C(19)-H(19B) 106.8

O(6)-C(10)-N(4) 117.3(4) C(19)-C(20)-C(21) 113.6(11)

O(6)-C(10)-C(7) 126.5(5) C(19)-N(5)-C(15) 100.5(8)

N(4)-C(10)-C(7) 116.2(5) C(11)-N(5)-C(15) 113.7(8)

O(1)-N(1)-O(2) 125.6(8) C(19)-N(5)-H(5A) 110.3

O(1)-N(1)-C(1) 118.4(9) C(11)-N(5)-H(5A) 110.1

O(2)-N(1)-C(1) 116.0(8) C(15)-N(5)-H(5A) 110.2

O(4)-N(2)-O(3) 126.7(8) C(12)-C(11)-N(5) 125.7(11)

O(4)-N(2)-C(3) 116.8(6) C(12)-C(11)-H(11A) 105.9

O(3)-N(2)-C(3) 116.3(6) N(5)-C(11)-H(11A) 105.9

86

C(12)-C(11)-H(11B) 105.9 H(15A)-C(15)-H(15B) 106.5

N(5)-C(11)-H(11B) 105.9 C(17)-C(16)-C(15) 119.3(13)

H(11A)-C(11)-H(11B) 106.3 C(17)-C(16)-H(16A) 107.5

C(11)-C(12)-C(13) 120.1(11) C(15)-C(16)-H(16A) 107.5

C(11)-C(12)-H(12A) 107.3 C(17)-C(16)-H(16B) 107.5

C(13)-C(12)-H(12A) 107.4 C(19)-C(20)-H(20A) 108.9

C(11)-C(12)-H(12B) 107.3 C(21)-C(20)-H(20A) 108.9

C(13)-C(12)-H(12B) 107.3 C(19)-C(20)-H(20B) 108.8

H(12A)-C(12)-H(12B) 106.9 C(21)-C(20)-H(20B) 108.8

C(14)-C(13)-C(12) 117.1(11) H(20A)-C(20)-H(20B) 107.7

C(14)-C(13)-H(13A) 108.0 C(22)-C(21)-C(22') 89(2)

C(12)-C(13)-H(13A) 108.0 C(22)-C(21)-C(20) 106.3(14)

C(14)-C(13)-H(13B) 108.1 C(22')-C(21)-C(20) 139.7(19)

C(12)-C(13)-H(13B) 108.1 C(21)-C(22)-H(22A) 124.4

H(13A)-C(13)-H(13B) 107.3 C(21)-C(22)-H(22B) 124.8

C(13)-C(14)-H(14A) 109.4 H(22A)-C(22)-H(22B) 90.9

C(13)-C(14)-H(14B) 109.5 C(21)-C(22)-H(22C) 124.8

H(14A)-C(14)-H(14B) 109.5 H(22A)-C(22)-H(22C) 90.8

C(13)-C(14)-H(14C) 109.5 H(22B)-C(22)-H(22C) 90.7

H(14A)-C(14)-H(14C) 109.5 C(21)-C(22')-H(22D) 109.9

H(14B)-C(14)-H(14C) 109.5 C(21)-C(22')-H(22E) 110.0

C(16)-C(15)-N(5) 123.0(11) H(22D)-C(22')-H(22E) 108.8

C(16)-C(15)-H(15A) 106.6 C(21)-C(22')-H(22F) 110.5

N(5)-C(15)-H(15A) 106.6 H(22D)-C(22')-H(22F) 108.8

C(16)-C(15)-H(15B) 106.6 H(22E)-C(22')-H(22F) 108.7

N(5)-C(15)-H(15B) 106.6

Table 16

Hydrogen-bond geometry (Å, °) of Complex 28

D–H…A d(D–H) d(D…H) d(D…A)

87

Fig. 19 ORTEP view of Complex 28

[C22 - disorder with an occupancy of 45%]

Fig. 20 Packing view of Complex 28

88

Table 17

Anticonvulsant activity of Complex 28 against MES

induced convulsion in Albino Rats

S.

No. Treatment

Time (sec) in various phases of convulsion

Flexor Extensor Clonus Stupor Recovery /

Death

1. Control

Normal Saline

(5 ml/kg)

3.24

±

0.09

13.30

±

0.25

9.24

±

0.21

137.00

±

8.24

Recovered

2. Complex 28

(25mg/kg)

8.00

±

1.50

12.00

±

2.40

28.00

±

3.20

43.00

±

1.20

Recovered

3. Complex 28

(50mg/kg)

7.00

±

2.10

10.00

±

2.10

16.00

±

1.40

38.00

±

1.30

Recovered

4. Complex 28

(100mg/kg)

3.50

±

0.08

3.40

±

0.51

4.10

±

0.82

93.20

±

5.80

Recovered

5. Phenytoin

(25mg/kg)

2.66

±

0.55

0.00

±

0.12

4.60

±

0.38

62.10

±

3.30

Recovered

Table 18

Hypnotic action of Complex 28

S.

No. Treatment

Dose

(mg/kg)

Time of

Admini-

stration

(mins)

(a)

Time

of loss

of

reflex

(mins)

(b)

On set

of action

(mins)

(b-a)

Time of

Recovery

(mins)

(c)

Duration

of action

(mins)

(c-b)

1 Control

Normal

saline

1 ml/kg

0 -- -- -- --

2 Complex 28 100 0 28.4 ±

3.35

28.4 ±

3.35

162.8 ±

3.6

134.4 ±

9.16

3 Phenobarbitone

Standard

20

mg/kg 0

16.40 ±

2.25

16.4 ±

2.25

257.9 ±

3.27

241.50 ±

5.90

89

Table 19

Data showing effect of Complex 28 on behavioural profiles of mice

Responses

Treatment

Score

(Normal Saline)

Score due to

Complex 28

Muscle Tone

Limp tone 4 4

Grip tone 4 4

Body tone 4 4

Abdominal tone 4 4

Reflexes

Pinna 4 3

Corneal 4 3

Writhing 0 0

Autonomic Profile

Urination 0 0

Salivation 0 0

Respiratory rate 4 4

Awareness

Alertness 0 0

Passivity 0 0

Aggression 0 0

Mood

Restlessness 0 0

Fearfulness 0 0

Touch response 4 4

Motor Activity

Pain response 4 4

Twitches 0 0

CNS excitation

Tremors 0 0

Convulsions 0 0

Body posture 4 4

Posture

Limb posture 4 4