Current Issues

2021 : Volume 1, Issue 1

Synthesis and Biological Significance of Novel 3,4,5-Substituted-1,2,4-Triazole

Author(s) : Dipanshu S 1 , Sucheta 1 , Prabhakar Kumar Verma 1 and Govind S 1

1 Department of Pharmaceutical Sciences , Maharshi Dayanand University , India

Open J Pharma Sci

Article Type : Research Article

Abstract

Background: 1,2,4-Triazole and its derivatives are important group of heterocyclic compounds characterized by a five-membered ring of two carbons and three nitrogen atoms and exhibited good pharmacological profile. A new class of 3,4,5-substituted-1,2,4-triazole scaffolds was synthesized and screened for its antimicrobial and analgesic activity.

Results and discussion: The synthesized 3,4,5-substituted-1,2,4-triazole derivatives were confirmed by 13C/1H-NMR and IR spectral data and evaluated its antimicrobial and analgesic activity. The synthesized derivatives showed good antimicrobial potential against Gram positive and Gram negative bacterial and fungal strains by tube dilution technique and analgesic activity by Tail immersion and Acetic acid induced writhing method and compared with standard drugs.

Conclusion: Especially compounds TA-11, TA-20 and TA-26 displayed more antimicrobial activity than standard drugs (cefadroxil (antibacterial) and fluconazole (antifungal) due to presence of electron withdrawing group. The compounds TA-13, TA-15 and TA-2, TA-15 exhibited good analgesic activity by Tail immersion and Acetic acid induced writhing method respectively due to presence of electron withdrawing group.

Keywords

1,2,4-Triazoles; Antibacterial; Antifungal; Analgesic

Background

The growing problem of antimicrobial resistance has induced additional urgency to design and develop novel types of antimicrobial agents with chemical structures different from the traditional drugs and improved the different types of biological activities. Heterocycles containing a 1,2,4-triazole or 1,3,4-thiadiazole moiety and the compounds consisting of 1,2,4-triazole and 1,3,4-thiadiazole condensed nucleus systems constitute a class of compounds possessing a wide spectrum of biological activity [1]. 1,2,4-Triazole and its derivatives are important group of heterocyclic compounds characterized by a five-membered ring of two carbons and three nitrogen atoms. 1,2,4-Triazole ring systems have been well studied and so far a variety of biological activities have been reported for a large number of their derivatives, such as anti-inflammatory, antianxiety, antimicrobial, antitubercular, antimycobacterial, anticancer, analgesic, diuretic and hypoglycemic properties [2].

The analgesic activity of opioids has been demonstrated in multiple species, including rodents and humans. In animal studies, the analgesic actions of these drugs are readily seen using a variety of analgesic assays, including the radiant heat tail-flick assay, which is one of the earliest paradigms used to assess analgesic drugs. Opioids produce their effects by activating specific opioid receptors. There are three major classes of opioid receptors, each with its own ligand selectivity. Most clinical drugs work through morphine-like receptors. Hydrocodone is a well-established opioid analgesic. Ibuprofen, a nonsteroidal anti-inflammatory drug is widely used for mild to moderate acute and chronic pain. Unlike opioids that have no ceiling effects on their analgesic activity, NSAID analgesia does display a ceiling effect and when given alone, has limited activity against severe pain. Opioids are often used in combination with NSAIDs and a number of products containing combinations are currently used widely in the management of pain. Preclinical studies have suggested interactions between NSAIDs in neuropathic and inflammatory pain models. In a model of chronic neuropathic pain, systemic ketorolac or piroxicam was found to synergize with spinal morphine. Others have observed interactions between opioids and NSAIDs in a range of inflammatory models where the NSAIDs would be expected to be active [3].

It was found that 1,2,4-triazole and its derivatives have diversified pharmacological activities, like synthesized 2,4-dihydro-1,2,4-triazol-3-one derivatives and found that it possesses antibacterial activity, synthesized 1-[(?-alkoxy-?-dialkylamino)propyl-1H-1,2,4-triazole and reported their antifungal activity, synthesized 5-phenyl-1-(3-pyridyl)-1H-1,2,4-triazole-3-carboxylic acid derivatives and found their anti-inflammatory activity, synthesized 3,4-disubstituted-5-mercapto-1,2,4-triazole derivatives and reported their analgesic activity, synthesized 4-benzylidenamino-4,5-dihydro-1H-1,2,4-triazole-5-ones and found their anti-oxidant activity, synthesized 3-[4-(3H)-quinazolinone-2-yl)thiomethyl]-1,2,4-triazole-5-thiols and reported their insecticidal activity, synthesized N`-[1-aryl-2-(1H-imidazol-1-yl and 1H-1,2,4-triazol-1-yl)-ethylidine]-pyridine-2-carboxami drazone derivatives and found their antitubercular activity [4-10].

The 1,2,4-triazole ring is a main pharmacophoric group responsible for antimicrobial and analgesic activity. Literature review revealed that di-substitution at 4 and 5 positions of 1,2,4-triazole-3-thiones is responsible for various biological activity. The marketed drugs containing 1,2,4-triazole ring as nucleus exhibiting antimicrobial activity are fluconazole, isavuconazole, anastrozole, letrozole, voriconazole (Figure 1).

 

 

Figure 1: Marketed drugs of 1,2,4-triazole.

 

Keeping this observation in mind, this work has presented the synthesis, antimicrobial, and analgesic activity of novel 3,4,5-substituted-1,2,4-triazole scaffolds.

Results and Discussion

Chemistry

In the study, we have reported a simple synthetic method for the synthesize of new class of 3,4,5-substituted-1,2,4-triazole derivatives (Scheme-1).


Scheme 1 (a): Synthesis of 3,4,5-substituted-1,2,4-triazole derivatives (TA-1 to TA-24)


Scheme 1 (b): Synthesis of 3,4,5-substituted-1,2,4-triazole derivatives (TA-25 to TA-27)

The procedure steps of the synthesized compounds were showing in experimental section. The molecular structures of the newly synthesized compounds were confirmed by 13C/1H-NMR, FT-IR spectral, Mass and elemental analysis and physicochemical properties (Table 1).

Compounds.

Molecular Formula

Molecular Weight

Melting points (oC)

Rf Value*

% Yield

TA-1.

C24H19N3O2S

413

210-215

0.74

66.7

TA-2.

C24H17Br2N3O2S

571

196-200

0.65

64.4

TA-3.

C12H11N3O4S

293

175-180

0.63

69.2

TA-4.

C24H19N3O3S

429

245-249

0.57

67.3

TA-5.

C24H17Br2N3O3S

587

240-245

0.66

65.2

TA-6.

C12H11N3O5S

309

185-190

0.85

64.8

TA-7.

C24H18ClN3O2S

448

230-235

0.88

65.3

TA-8.

C24H16Br2ClN3O2S

606

175-180

0.82

69.2

TA-9.

C12H10ClN3O4S

328

248-253

0.75

71.3

TA-10.

C24H18ClN3O2S

448

140-144

0.78

60.7

TA-11.

C24H16Br2ClN3O2S

606

180-185

0.68

68.3

TA-12.

C12H10ClN3O4S

328

130-134

0.71

59.8

TA-13.

C24H18ClN3O2S

448

230-235

0.74

74.1

TA-14.

C24H16Br2ClN3O2S

606

190-195

0.82

57.6

TA-15.

C12H10ClN3O4S

328

180-185

0.69

72.0

TA-16.

C24H18BrN3O2S

492

208-213

0.71

55.7

TA-17.

C24H16Br3N3O2S

650

135-140

0.58

75.8

TA-18.

C12H10BrN3O4S

372

144-149

0.65

44.6

TA-19.

C24H18IN3O2S

539

173-178

0.77

73.7

TA-20.

C24H16Br2IN3O2S

697

145-150

0.68

75.5

TA-21.

C12H10IN3O2S

419

225-230

0.75

76.04

TA-22.

C24H18N4O4S

458

160-165

0.62

79.14

TA-23.

C24H16Br2N4O4S

616

200-205

0.65

55.8

TA-24.

C12H10N4O6S

338

230-234

0.67

57.1

TA-25.

C25H19Cl2N3O3S

512

135-140

0.84

73.8

TA-26.

C25H17Br2Cl2N3O3S

670

115-120

0.87

76.4

TA-27.

C13H11Cl2N3O5S

392

125-130

0.72

58.6


Table 1: The physicochemical properties of synthesized 3,4,5-substituted-1,2,4-triazole derivatives.
*TLC mobile phase: benzene; Chloroform:nHexene

The elemental analysis results of the newly synthesized compounds were within ± 0.39% of the theoretical values.

The chemical structures of the synthesized 3,4,5-substituted-1,2,4-triazole derivatives (TA-1 to TA-27) were confirmed by FT-IR (KBr pellets, cm-1) and 1H/13C-NMR (CDCl3, ? ppm) spectral, mass and elemental studies. The appearance of IR absorption band at 3467-3331 cm-1 in the spectral data of synthesized derivatives (TA-3 toTA-6, TA-9, TA-12, TA-15, TA-18, TA-21, TA-24 and TA-27) displayed the presence of -OH group. The existence of Ar-NO2 group symmetric and asymmetric Ar-NO2 stretches in the scale of 1388-1334 cm-1 and 1519-1511 cm-1 respectively. The impression of IR stretching vibration at 3162-3120 cm-1 and 1573-1511 cm-1 in the spectral data of synthesized compounds specified the existence of C-H and C=C group respectively. The appearance of IR stretching 1596-1511 cm-1 and 1384-1314 cm-1 in the spectral data of all synthesized compounds specified the existence of C=N and C-N groups respectively. The IR absorption band in the scale of 646 cm-1 to 621 cm-1 corresponds to the C-Br stretching of aromatic-bromo compounds (TA-2, TA-5, TA-8, TA-11, TA-14, TA-17, TA-20, TA-23 and TA-26). The impression of IR stretching vibration at 867-811 cm-1 and 1846-1723 cm-1 in the spectral data of synthesized compounds specified the existence of C-S and C=O groups respectively. The IR absorption band in the scale of 741 cm-1 to 719 cm-1 corresponds to the C-Cl stretching of aromatic-Chloro compounds (TA-7 to TA-11, TA-13 toTA-15 and TA-25 to TA-27). The IR absorption band in the scale of 634 cm-1 to 623 cm-1 corresponds to the C-I stretching of aromatic-Iodo compounds (TA-19 to TA-21). The impression of IR stretching vibration at 2887-2816 cm-1 in the spectral data of synthesized compounds specified the existence of C-H group of -CH2. The multiplet signals between 6.23-8.91 ? ppm in 1H-NMR spectra is indicative of aromatic proton of synthesized derivatives. The synthesized derivatives (TA-3, TA-6, TA-9, TA-12, TA-15, TA-18, TA-21, TA-24 and TA-27) showed singlet at 9.01-11.21 ? ppm due to the existence of OH group of COOH. Compounds TA-4, TA-5 and TA-6 showed singlet at 5.20-5.36 ? ppm due to the existence of Ar-OH group. All compounds showed singlet at 3.87-4.19 ? ppm due to the existence of CH2. Compounds, TA-1, TA-4, TA-7, TA-10, TA-13, TA-16, TA-19, TA-22 and TA-25 showed singlet at 2.45-2.67 ? ppm due to existence of -CH3. The elemental screened studies of the 3,4,5-substituted-1,2,4-triazole derivatives were found within ± 0.39 % of the theoretical results.

Biological study

Antimicrobial activity


The antimicrobial activity: MIC (minimum inhibitory concentration) of the synthesized 3,4,5-substituted-1,2,4-triazole derivatives was evaluated for their antibacterial activity against three strains (two of Gram positive and one Gram negative): Staphylococcus aureus MTCC 3160, Bacillus subtilis MTCC 441 (Gram positive bacteria), Escherichia coli MTCC-443 (Gram negative bacteria) and fungal strains: Aspergillus niger MTCC 281 and Candida albicans MTCC 227 was done by tube dilution technique [11]. Test compounds and standard drug ciprofloxacin were dissolved in dimethylsulphoxide (DMSO) to prepare a stock solution of the concentration 100 ?g/mL. MIC was evaluated for six different concentrations of each test compound and the standard drug. These different concentrations were obtained by serial dilution in nutrient broth medium (antibacterial study) and sabouraud dextrose broth (antifungal study). The six different concentrations were 50, 25, 12.5, 6.25, 3.12 and 1.56 ?g/mL. Then, 0.1 mL of normal saline suspension of revived bacteria was added to each test tube and cotton plug was plugged close the top of test tubes. The inoculated tubes were incubated at 37 oC for 24 h. Following the completion of incubation period turbidity was measured to determine the MIC (Table 2)

Comp. No.

Minimum inhibitory concentration (?M/mL)

Bacterial species

Fungal species

S. aureus

B. subtilis

E. coli

C. albicans

A. niger

TA-1.

0.76

0.38

0.38

0.76

1.51

TA-2.

0.55

0.27

0.27

1.09

2.19

TA-3.

2.13

0.53

0.53

1.06

4.27

TA-4.

0.73

0.36

0.36

1.46

1.46

TA-5.

0.53

0.53

0.53

1.06

1.06

TA-6.

1.01

1.01

0.50

2.02

1.01

TA-7.

0.70

0.35

0.35

0.70

1.40

TA-8.

0.51

0.26

0.26

0.51

2.06

TA-9.

0.95

7.62

0.48

1.91

1.91

TA-10.

1.40

0.35

0.70

0.70

2.79

TA-11.

1.03

1.03

0.51

0.26

0.51

TA-12.

0.95

0.95

0.95

1.91

1.91

TA-13.

0.70

0.70

0.35

1.40

0.70

TA-14.

1.03

0.51

0.26

1.03

1.03

TA-15.

1.91

0.48

0.48

0.48

0.95

TA-16.

0.63

0.32

0.32

1.27

0.63

TA-17.

0.96

0.48

0.24

0.48

0.96

TA-18.

0.84

0.42

0.42

0.84

1.68

TA-19.

0.58

1.16

0.29

0.58

1.16

TA-20.

0.45

0.45

0.22

0.90

0.45

TA-21.

0.74

0.74

0.37

0.74

1.49

TA-22.

0.68

0.68

0.34

1.36

2.73

TA-23.

0.51

2.03

0.25

0.51

1.01

TA-24.

0.92

7.40

0.46

1.85

3.70

TA-25.

0.61

4.88

0.30

1.22

2.44

TA-26.

0.93

0.23

0.23

0.47

0.93

TA-27.

0.80

1.59

0.40

1.59

1.59

Std.

1.72a

1.72a

1.72a

2.04b

2.04b

Table 2: Minimum inhibitory concentration of 3,4,5-substituted-1,2,4-triazole analogues
 aCefadroxil; bFluconazole

Antimicrobial activity results indicated that in the case of Gram +ve bacterial study, compound TA-20 was found to be most potent against S. aureus with MIC value = 0.45 µM/mL and compound TA-26 was found to be most potent against B. subtilis with MIC value = 0.23 µM/mL. In the case of Gram-ve bacterial study, compound TA-20 (MICec = 0.22 µM/mL) was the most active one against E. coli. The antifungal activity results indicated that compounds TA-11 (MICca = 0.26 µM/mL) and compound TA-20 (MICan= 0.45 µM/mL) were found to be most effective ones against C. albicans and A. niger respectively. The antimicrobial activity result of synthesized compounds is comparable to the reference drugs, ciprofloxacin (antibacterial) and fluconazole (antifungal) studies.

Analgesic activity

Analgesic activity by Tail immersion method (for central action)

The study was carried out on healthy male Wister albino rats weighing between 70-120 g. The animals were divided into number of groups, each groups contain six animals. The animals were subjected to fasting overnight before administration. Ibuprofen used as standard drug: dose of 20 mg/kg body weight of rats was made in acacia suspension. Selected 1,2,4-triazole derivatives: dose of test compounds was 20 mg/kg body weights of rats. Control acacia suspension: 3.0 % w/v suspension was made in distilled water. Routes of administration: the test compounds and standard drugs were suspended in 3.0 % w/v acacia suspension was given by oral route by intubation. The Rats were divided into 11 groups, containing six animals in each group. These animals were fasted overnight, prior to the experiment. Animals of group-1 were considered as control and administered with 3 % acacia suspension. Animals of group-2 were treated with standard drug, i.e., Ibuprofen (20 mg/kg), which were considered as standard group. Animals of group 3-11 were treated with nine different synthesized novel drugs (20 mg/kg) respectively. The tolerance latency of each rat were recorded at time interval of 15 min, 30 min, 45 min, 60 min, 90 min and 120 min after the administration of test drugs by using tail immersion in hot water which was maintained at 51 oC. The percent analgesic activity (PAA) was calculated by the following formula: PAA = (T2- T1/T1) × 100

T1 is the basal latency (i.e. before any drug treatment) and T2 is the tolerance latency (i.e. after drug treatment) [12].

Statistical analysis

All the results were expressed as mean ± standard error of mean (SEM). Data was analyzed using student t-test and critical range for significance difference between two groups of observations was taken as p< 0.05, p<0.01 and P<0.001.

There was no increase in percent analgesic activity in control group. There was significant increase in percent analgesic activity till 60 min after that there was decrease in percent analgesic activity in standard drug group. There was increase in percent analgesic activity after 15 min, the group showed good activity after 45 min there after there was decrease in percent analgesic activity for a group administered with compound TA-1. The presented results are indicated in (Table 3)


Sr. No.

Compound

% Analgesic Activity ± SEM

15 min

30 min

45 min

60 min

90 min

120 min

1.

Control

11 ± 7

11 ± 7

11 ± 7

11 ± 7

11 ± 7

11 ± 7

2.

Standard

86 ± 19***

153 ± 24***

203 ± 23

236 ± 19***

209 ± 21***

203 ± 23***

3.

TA-1.

28 ± 10

128 ± 10***

156 ± 11

150 ± 8***

117 ± 7***

78 ± 7*

4.

TA-2.

50 ± 6

135 ± 9***

170 ± 11

164 ± 9***

83 ± 22*

75 ± 17*

5.

TA-4.

17 ± 7

135 ± 9***

144 ± 6

129 ± 7***

119 ± 9***

85 ± 7**

6.

TA-7.

17 ± 6

82 ± 6*

122 ± 11**

107 ± 9***

100 ± 9**

77± 5*

7.

TA-10.

17 ± 5

46 ± 9

75 ± 11***

61 ± 14

46 ± 9

46 ± 9

8.

TA-13.

67 ± 15**

109 ± 19

125 ± 27*

192 ± 26***

158 ± 27***

109 ± 19***

9.

TA-15.

17 ± 7***

150 ± 6***

175 ± 8

161 ± 9***

140 ± 6***

125 ± 10***

10

TA-17.

22 ± 7

30 ± 2

53 ± 9***

57 ± 7

47 ± 9

42 ± 8

11.

TA-18.

17 ± 6

46 ± 9

104 ± 13***

94 ± 14**

42 ± 120

50 ± 8

Table 3: Percent analgesic activity by Tail immersion method

The percent analgesic values are Mean ± SEM from 6 animals in each group.
Statistical analysis was done by student’s unpaired t-test
 *p< 0.05, **p< 0.01, ***p<0.001 compared with control

The group-4 administered with compound TA-2, showed good activity at 45 min after there was decrease in percent analgesic activity for a group. The onset of action was significantly seen after 15 min and drug action was remaining till 45 min, after that there was decrease in percent analgesic activity for compound TA-4. There was significantly increase in percent analgesic activity after till 45 min there after there was decrease in percent analgesic activity for a group administered with compound TA-7. The moderate increase in percent analgesic activity was seen with compound TA-10. Compound TA-13 showed good analgesic effect and after 1 h analgesic effect was started to decrease. The moderate increase in percent analgesic activity was seen with compound TA-15, TA-17 and TA-18.

Analgesic activity by acetic acid induced writhing method (for peripheral action): 

The study was carried out on healthy male Wister albino rats weighing between 70-120 g. The animals were divided into number of groups of six animals. The animals were subjected to fasting overnight before administration. Ibuprofen used as standard drugs: dose of 20 mg/kg body weight of rats was made in acacia suspension. Selected 3,4,5-substituted-1,2,4-triazole derivatives: dose of test compounds was 20 mg/kg body weights of rats. Control: acacia suspension: 3.0 % w/v suspension was made in distilled water. Analgesia; acetic acid saline solution: a solution of 0.7% acetic was made in acid saline. Routes of administration: The test compounds and standard drugs were suspended in 3.0 % w/v acacia suspension was given by oral route by intubation. Procedure for analgesic activity by acetic acid induced writhing method is as follows: rats were divided into 11 groups, containing six animals in each group. These animals were fasted overnight, prior to the experiment. Animals of group-1 were considered as control and administered with 3 % acacia suspension. Animals of group-2 were treated with standard drug, i.e., ibuprofen (20 mg/kg), which were considered as standard group. Animals of group 3-11 were treated with nine different synthesized novel drugs (20 mg/kg) respectively. After 30 min of oral administration of suspension of as mentioned dose, an injection of 1 mL of 0.7% v/v acetic acid saline per 100 g weight of rat was injected (i.p). After 10 min of injection number of writhing during the 20 min period was counted.
The % analgesic activity was calculated by:
% analgesic activity = (N-Nt / Nt) × 100
Where, N = Average number of stretching of control per group
Nt = Average number of stretching of test per group [13].
The presented results of analgesic activity by acetic acid-induced writhing method are indicated in (Table 4)

Sr. No.

Compound

Percent Analgesic Activity (%)

1.

Control

0

2.

Standard

440

3.

TA-1.

227

4.

TA-2.

800

5.

TA-4.

237

6.

TA-7.

181

7.

TA-10.

98

8.

TA-13.

26

9.

TA-15.

484

10.

TA-17.

20

11.

TA-18.

96

Table 4: Percent analgesic activity by Acetic acid-induced writhing method

The test compounds showed significant analgesic activity (Figure 2)


Figure 2: Percent analgesic activity by acetic acid-induced writhing method

when compared with standard. Compounds TA-1, TA-4 and TA-7 were found to have moderate analgesic activity, while compounds, TA-2 and TA-15 were found to be good analgesic activity as compared to standard drugs. All the compounds showed appreciable analgesic activity.

SAR (Structure Activity Relationship) studies

From the antimicrobial and analgesic activities results of the synthesized 3,4,5-substituted-1,2,4-triazole analogues, the subsequent structure activity relationship can be derived in (Figure 3).


Figure 3: Structure activity relationship of the synthesized 3,4,5-substituted-1,2,4-triazole analogues


1. Presence of 1-(4-bromophenyl)propan-1-one group (Compounds TA-11, TA-20 and TA-26) enhanced the antimicrobial potential of the synthesized compounds against C. albicans, B. subtilis, S. aureus, A. niger and E. coli..

2. Presence of electron withdrawing group (-Cl, Compounds TA-11 and TA-26) on benzylidene portion improved the antimicrobial activity of the synthesized compounds against C. albicans and B. subtilis respectively and (-I, Compound TA-20) on benzylidene portion improved the antimicrobial activity of the synthesized compounds against S. aureus, A. niger and E. coli.

3. Presence of electron withdrawing groups (-Br, Compound TA-2 and –Cl, Compound 15) at para position of benzylidene portion improved the analgesic activity by acetic acid induced writhing method and (-Cl, Compound TA-2 and Compound TA-15) at para position of benzylidene portion improved the analgesic activity by Tail immersion method 

Experimental Section

All the chemicals and reagents employed for the synthetic work were purchased from Loba Chemie Lab. Pvt Lmt, Mumbai; HiMedia Laboratories Pvt Ltd, Mumbai; Sisco Research Laboratory, Mumbai and Central Drug House, Pvt Ltd, Mumbai; Thomas Baker (Chemicals) Pvt. Ltd, Mumbai. Melting points were determined by open capillary method with a Lab Tech-Melting Point Apparatus and were uncorrected. IR spectra study of the compounds was recorded on a Shimadzu FT-IR-8300 spectrophotometer. The Mass spectral data were confirmed by Waters Micromass Q-ToF Micro instrument. 1H-NMR/13C-NMR spectra study of the compounds was recorded on an Agilent NMR 4300 MHz spectrometer using DMSO solvent. Chemical shift values are given in d scales. Elemental analyses were performed on a Flash 2000 series CHNS–O analyzer. The completion of the reaction was checked by thin layer chromatography (TLC) on silica gel coated aluminum sheets (Silica Gel 60 F254).

Procedure of 3,4,5-Substituted-1,2,4-triazole derivatives (TA-1 to TA-27)

Step i: Synthesis of ethyl substituted benzoate/ethyl 2-(2,4-dichlorophenoxy)acetate

A mixture of 0.1 mole of pure substituted benzoic acid/ 2-(2,4-dichlorophenoxy)acetic acid, 0.13 mole of conc. sulphuric acid, 0.4 mole of absolute ethanol were taken in a 500 mL of round bottom flask and refluxed on heating mantle at temperature 60oC for 4-5 h and checked by TLC and then allowed to cool after that poured the residue into about 250 mL of water in a separating funnel and rinsed the flask with a few mL of water which were also poured into separating funnel and shook the mixture in the funnel vigorously; upon standing the ethyl ester of aryl carboxylic acid separated sharply and rapidly at the bottom of the separating funnel. Lower layer of ester was collected at the bottom and upper aqueous layer was rejected, returned the ethyl ester of aryl carboxylic acid to the beaker and shook with a strong solution of potassium hydrogen carbonate until all free acid was neutralized and no further evolution of carbon dioxide occurred. Washed once with water, and dried by pouring into a dry china dish containing about 2 gm of magnesium sulphate. 

Step ii: Synthesis of substituted benzohydrazide/2-(2,4-dichlorophenoxy)acetohydrazide

A mixture of 0.1 mole of ethyl substituted benzoate/ethyl 2-(2,4-dichlorophenoxy) acetate and 0.116 moles of hydrazine hydrate was refluxed with 25.5 mL of absolute ethanol for 6-7 h and checked by TLC. Then excess of ethanol was distilled off, the reaction mixture was cooled and then substituted benzohydrazide/2-(2,4-dichlorophenoxy)acetohydrazide was purified by dissolving in small quantity of ethanol after that the excess of ethanol was distilled off and the product was dried and recrystallized with ethanol. 

Step iii: Synthesis of 1-(substituted benzoyl)thiosemicarbazide/1-(2-(2,4-dichlorophenoxy) acetyl)thiosemicarbazide

A mixture of 0.1 mole of substituted benzohydrazide/2-(2,4-dichlorophenoxy) acetohydrazide and 0.12 moles of potassium thiocyanate was taken in a 500 mL of round bottom flask. 20 mL of 10% hydrochloric acid solution was added drop wise to this mixture and refluxed for 3-4 h and checked by TLC. The solid crude product was separated out by filtration and washed with sufficient quantity of water and then dried. 

Step iv: Synthesis of 5-(substituted phenyl)-4H-1,2,4-triazole-3-thiol/5-((2,4-dichloro phenoxy)methyl)-4H-1,2,4-triazole-3-thiol

5 mL solution of 2 M sodium hydroxide (8% solution) was added portion wise to 0.01 mole of solid 1-(substituted benzoyl)thiosemicarbazide/1-(2-(2,4-dichlorophenoxy)acetyl) thiosemicarbazide and stirred well. Then refluxed for 4-5 h and checked by TLC. After the completion of reaction, the reaction mixture was treated with activated charcoal and filtered. Then filtrate was acidified with hydrochloric acid for pH 6 and the precipitate was filtered and recrystallized with ethanol/water. Then the product was dried. 

Step v: Synthesis of final 3,4,5-substituted-1,2,4-triazole derivatives (1-27)

The 0.01 mole of 5-(substituted phenyl)-4H-1,2,4-triazole-3-thiol/5-((2,4-dichloro phenoxy)methyl)-4H-1,2,4-triazole-3-thiol was dissolved in 0.01 mole of potassium carbonate solution. Then 0.02 mole of substituted acetophenone was added to this mixture. Then this mixture was refluxed for 5-6 h and reaction was checked by TLC. The hot reaction mixture was treated with activated charcoal, and then filtered and filtrate was acidified with dilute HCl solution till pH 6. The product was thus precipitated out, filtered, washed with water and recrystallized by ethanol/water (1:1). 

Spectral data of the synthesized compounds 


Sr No.

Compound Name

IR (KBR cm-1)

MS ES + (ToF)

1H-NMR, ? ppm (DMSO-d6);

 

13H-NMR, ? ppm (DMSO-d6):

Elem. Anal. Calcd.

1

1-(4-((4-(4-Acetylphenyl)-5-phenyl-4H-1,2,4-triazol-3-yl)thio)phenyl)ethanone (TA-1)

3122 (C-H str.), 1573 (C=C str.), 1845 (C=O str.), 2867 (C-H str., CH3) 1566 (C=N str.), 1384 (C-N str.), 813 (C-S str.)

m/z 414 [M+ +1]

7.22-7.90 (m, 13H, Ar-H) i.e. presence of three phenyl rings and 2.58 {s, 6H, (CH3)2} i.e. presence of two acetyl groups; 13H-NMR, ? ppm (DMSO-d6): 15.2, 26.1, 126.4, 127.6, 128.5, 129.5, 129.3, 131.1, 132.1, 133.4, 134.3, 136.2, 137.3, 147.7, 153.5, 160.5, 197.1;

C24H19N3O2S: C, 69.71; H, 4.63; N, 10.16; Found: C, 69.61; H, 4.43; N, 10.26

2

1-(4-Bromophenyl)-2-((4-(2-(4-bromophenyl)-2-oxoethyl)-5-phenyl-4H-1,2,4-triazol-3-yl) thio)ethanone (TA-2)

3122 (C-H str.), 1523 (C=C str.), 1745 (C=O str.), 2877 (C-H str., CH2), 1576 (C=N str.), 1374 (C-N str.), 818 (C-S str.), 645 (Ar-Br str.)

m/z 572 [M+ +1]

7.22-7.75 (m, 13H, Ar-H) i.e. presence of three phenyl rings, 4.19 (s, 2H, S-CH2) and 4.99 (s, 2H, N-CH2) i.e. presence of two acetyl groups; 13H-NMR, ? ppm (DMSO-d6): 38.6, 48.1, 126.7, 127.2, 128.9, 129.4, 130.8, 131.1, 132.1, 133.4, 134.3, 136.2, 137.3, 147.7, 153.5, 160.5, 190.1,194.8

C24H17Br2N3O2S: C, 50.46; H, 3.00; N, 7.36; Found: C, 50.42; H, 3.34; N, 7.37

3

2-((4-(Carboxymethyl)-5-phenyl-4H-1,2,4-triazol-3-yl)thio)acetic acid (TA-3)

3162 (C-H str.), 1526 (C=C str.), 1755 (C=O str.), 2875 (C-H str., CH2), 1546 (C=N str.), 1364 (C-N str.), 818 (C-S str.), 3464 (OH str.)

m/z 294[M+ +1]

7.22-7.48 (m, 5H, Ar-H) i.e. presence of one phenyl ring and 3.87 (s, 2H, S-CH2) and 4.67 (s, 2H, N-CH2) and 11.21 (s, 1H, OH) i.e. presence of two carboxylic groups; 13H-NMR, ? ppm (DMSO-d6): 34.5, 42.5, 126.6, 127.15, 129.4, 130.4, 131.1, 132.5, 134.3, 147.7, 153.5, 174.9, 149.2, 171.5

C12H11N3O4S: C, 49.14; H, 3.78; N, 14.33; Found: C, 49.19; H, 3.74; N, 14.39

4

1-(4-((4-(4-Acetylphenyl)-5-(2-hydroxyphenyl)-4H-1,2,4-triazol-3-yl)thio)phenyl)ethanone (TA-4)

3120 (C-H str.), 1563 (C=C str.), 1846 (C=O str.), 2887 (C-H str., CH3), 1596 (C=N str.), 1374 (C-N str.), 833 (C-S str.); 3382 (OH str.)

m/z 430[M+ +1]

7.24-7.90 (m, 12H, Ar-H) i.e. presence of three phenyl rings and 2.52 {s, 6H, (CH3)2} i.e. presence of two acetyl groups, 5.30 (s, 1H, Ar-OH); 13H-NMR, ? ppm (DMSO-d6): 26.1, 117.4, 118.7, 121.8, 127.6, 128.5, 129.5, 131.0, 133.4, 136.4, 137.3, 147.7, 153.6, 154.3, 160.5, 197.0

C24H19N3O3S: C, 67.12; H, 4.46; N, 9.78; Found: C, 67.15; H, 4.41; N, 9.69

5

1-(4-Bromophenyl)-2-((4-(2-(4-bromophenyl)-2-oxoethyl)-5-(2-hydroxyphenyl)-4H-1,2,4-triazol-3-yl)thio)ethanone (TA-5)

3121 (C-H str.), 1523 (C=C str.), 1745 (C=O str.), 2877 (C-H str., CH2), 1522 (C=N str.), 1344 (C-N str.), 815 (C-S str.), 643 (Ar-Br str.), 3331 (OH str.)

m/z 588[M+ +1]

7.22-7.78 (m, 12H, Ar-H) i.e. presence of three phenyl rings, 4.19 (s, 2H, S-CH2) and 4.45 (s, 2H, N-CH2) i.e. presence of two acetyl groups; 5.2 (s, 1H, Ar-OH); 13H-NMR, ? ppm (DMSO-d6): 38.9, 48.3, 117.5, 118.9, 122.5, 127.8, 129.2, 130.8, 131.0, 132.1, 133.4, 134.1, 149.7, 153.5, 154.4, 190.0, 194.9

C24H17Br2N3O3S: C, 49.08; H, 2.92; N, 7.15; Found: C, 49.12; H, 2.98; N, 7.19

6

2-((4-(Carboxymethyl)-5-(2-hydroxyphenyl)-4H-1,2,4-triazol-3-yl)thio)acetic acid (TA-6)

3122 (C-H str.), 1562 (C=C str.), 1836 (C=O str.), 2887 (C-H str., CH2) 1596 (C=N str.), 1374 (C-N str.), 831 (C-S str.), 3332 (OH str.)

m/z 310 [M+ +1]

7.22-7.48 (m, 4H, Ar-H) i.e. presence of one phenyl ring and 4.87 (s, 2H, S-CH2) and 4.64 (s, 2H, N-CH2) and 10.1 (s, 1H, COOH), 4.90 (s, 1H, Ar-OH); 13H-NMR, ? ppm (DMSO-d6): 34.5, 43.5, 117.8, 118.7, 121.6, 130.2, 131.5, 149.7, 153.5, 154.3, 174.9

C12H11N3O5S: C, 46.60; H, 3.58; N, 13.59; Found: C, 46.67; H, 3.51; N, 13.63

7

-((4-(4-Acetylphenyl)-5-(2-chlorophenyl)-4H-1,2,4-triazol-3-yl)thio)phenyl)ethanone (TA-7)

3120 (C-H str.), 1561 (C=C str.), 1843 (C=O str.), 2847 (C-H str., CH3), 1594 (C=N str.), 1354 (C-N str.), 833 (C-S str.); 719 (C-Cl, Ar-Cl str.)

m/z 449 [M+ +1]

7.35-7.89 (m, 12H, Ar-H) i.e. presence of three phenyl rings and 2.51 {s, 6H, (CH3)2} i.e. presence of two acetyl groups; 13H-NMR, ? ppm (DMSO-d6): 25.1, 126.4, 127.5, 128.7, 129.5, 129.3, 132.1, 133.7, 134.0, 136.4, 137.6, 147.1, 152.7, 160.0, 196.1

C24H18ClN3O2S: C, 64.35; H, 4.05; N, 9.38; Found: C, 64.39; H, 4.09; N, 9.43

8

1-(4-Bromophenyl)-2-((4-(2-(4-bromophenyl)-2-oxoethyl)-5-(2-chlorophenyl)-4H-1,2,4-triazol-3-yl)thio)ethanone (TA-8)

3122 (C-H str.), 1522 (C=C str.), 1745 (C=O str.), 2817 (C-H str., CH2), 1511 (C=N str.), 1344 (C-N str.), 815 (C-S str.), 733 (C-Cl, Ar-Cl str.), 621 (C-Br, Ar-Br str.)

m/z 607 [M+ +1]

7.20-7.95 (m, 12H, Ar-H) i.e. presence of three phenyl rings, 4.89 (s, 2H, S-CH2), 5.45 (s, 2H, N-CH2) i.e. presence of two acetyl groups; 13H-NMR, ? ppm (DMSO-d6): 38.6, 48.1, 127.2, 128.0, 129.1, 130.8, 131.1, 132.3, 133.4, 138.3, 153.8, 190.0, 194.6

C24H16Br2ClN3O2S: C, 47.59; H, 2.66; N, 6.94; Found: C, 47.62; H, 2.69; N, 6.91

9

2-((4-(Carboxymethyl)-5-(2-chlorophenyl)-4H-1,2,4-triazol-3-yl)thio)acetic acid (TA-9)

3131 (C-H str.), 1542 (C=C str.), 1742 (C=O str.), 2837 (C-H str., CH2), 1513 (C=N str.), 1334 (C-N str.), 814 (C-S str.), 733 (C-Cl, Ar-Cl str.), 3463 (OH str.);

m/z 329 [M+ +1]

7.30-7.74 (m, 4H, Ar-H) i.e. presence of one phenyl ring and 4.20 (s, 2H, S-CH2) and 4.56 (s, 2H, N-CH2) and 10.11 (s, 1H, OH) i.e. presence of two carboxylic groups; 13H-NMR, ? ppm (DMSO-d6): 34.5, 43.5, 128.15, 129.4, 130.4, 132.2, 138.3, 149.7, 153.8, 174.9, 149.2, 171.0

C12H10ClN3O4S: C, 43.98; H, 3.08; N, 12.82; Found: C, 43.96; H, 3.13; N, 12.79

10

1-(4-((4-(4-Acetylphenyl)-5-(3-chlorophenyl)-4H-1,2,4-triazol-3-yl)thio)phenyl)ethanone (TA-10)

3123 (C-H str.), 1534 (C=C str.), 1734 (C=O str.), 2867 (C-H str., CH3), 1512 (C=N str.), 1343 (C-N str.), 817 (C-S str.), 734 (C-Cl, Ar-Cl str.)

449 [M+ +1]

): 7.25-8.75 (m, 12H, Ar-H) i.e. presence of three phenyl rings and 2.45 {s, 6H, (CH3)2} i.e. presence of two acetyl groups; 13H-NMR, ? ppm (DMSO-d6): 26.1, 125.7, 126.1, 127.6, 128.7, 129.0, 129.1, 129.3, 132.5, 133.6, 136.3, 137.6, 147.2, 152.6, 159.0, 197.0

C24H18ClN3O2S: C, 64.35; H, 4.05; N, 9.38; Found: C, 64.38; H, 4.10; N, 9.14

11

1-(4-Bromophenyl)-2-((4-(2-(4-bromophenyl)-2-oxoethyl)-5-(3-chlorophenyl)-4H-1,2,4-triazol-3-yl)thio)ethanone (TA-11)

3123 (C-H str.), 1526 (C=C str.), 1741 (C=O str.), 2816 (C-H str., CH2), 1526 (C=N str.), 1367 (C-N str.), 867 (C-S str.), 739 (C-Cl, Ar-Cl str.), 626 (C-Br, Ar-Br str.)

m/z 607 [M+ +1]

7.34-7.80 (m, 12H, Ar-H) i.e. presence of three phenyl rings, 4.45 (s, 2H, S-CH2) and 5.35 (s, 2H, N-CH2) i.e. presence of two acetyl groups; 13H-NMR, ? ppm (DMSO-d6): 38.6, 47.1, 127.9, 128.2, 128.0, 129.7, 130.8, 131.5, 133.4, 134.8, 138.3, 149.4, 153.8, 190.0, 194.1

C24H16Br2ClN3O2S: C, 47.59; H, 2.66; N, 6.94; Found: C, 47.63; H, 2.61; N, 6.87

12

2-((4-(Carboxymethyl)-5-(3-chlorophenyl)-4H-1,2,4-triazol-3-yl)thio)acetic acid (TA-12)

3123 (C-H str.), 1546 (C=C str.), 1787 (C=O str.), 2833 (C-H str., CH2), 1541 (C=N str.), 1384 (C-N str.), 814 (C-S str.), 731 (C-Cl, Ar-Cl str.), 3467 (OH str.)

m/z 329[M+ +1]

7.40-8.70 (m, 4H, Ar-H) i.e. presence of one phenyl ring and 4.26 (s, 2H, S-CH2) and 4.59 (s, 2H, N-CH2) and 11.01 (s, 1H, OH) i.e. presence of two carboxylic groups; 13H-NMR, ? ppm (DMSO-d6): 34.5, 43.5, 125.8, 128.15, 128.5, 129.4, 130.4, 134.2, 138.3, 149.5, 153.9, 174.9, 149.2, 171.0

C12H10ClN3O4S: C, 43.98; H, 3.08; N, 12.82; Found: C, 43.94; H, 3.13; N, 12.88

13

1-(4-((4-(4-Acetylphenyl)-5-(4-chlorophenyl)-4H-1,2,4-triazol-3-yl)thio)phenyl)ethanone (TA-13)

3132 (C-H str.), 1562 (C=C str.), 1741 (C=O str.), 2857 (C-H str., CH3), 1511 (C=N str.), 1314 (C-N str.), 814 (C-S str.), 731 (C-Cl, Ar-Cl str.)

m/z 449 [M+ +1]

7.29-7.90 (m, 12H, Ar-H) i.e. presence of three phenyl rings and 2.57 {s, 6H, 2-(CH3)2} i.e. presence of two acetyl groups; 13H-NMR, ? ppm (DMSO-d6): 26.5, 128.7, 129.0, 129.2, 132.6, 133.8, 134.0, 136.2, 137.6, 147.5, 153.6, 160.0, 198.0

C24H18ClN3O2S: C, 64.35; H, 4.05; N, 9.38; Found: C, 64.39; H, 4.10; N, 9.33

14

1-(4-Bromophenyl)-2-((4-(2-(4-bromophenyl)-2-oxoethyl)-5-(4-chlorophenyl)-4H-1,2,4-triazol-3-yl)thio)ethanone (TA-14)

3156 (C-H str.), 1556 (C=C str.), 1743 (C=O str.), 2847 (C-H str., CH2), 1512 (C=N str.), 1343 (C-N str.), 814 (C-S str.), 734 (C-Cl, Ar-Cl str.), 624 (C-Br, Ar-Br str.)

m/z 607 [M+ +1]

7.33-7.75 (m, 12H, Ar-H) i.e. presence of three phenyl rings, 4.16 (s, 2H, S-CH2) and 4.72 (s, 2H, N-CH2) i.e. presence of two acetyl groups; 13H-NMR, ? ppm (DMSO-d6): 38.4, 47.2, 127.4, 128.5, 129.7, 131.8, 133.4, 134.5, 149.2, 153.4, 190.0, 194.1

C24H16Br2ClN3O2S: C, 47.59; H, 2.66; N, 6.94; Found: C, 47.63; H, 2.68; N, 6.89

15

2-((4-(Carboxymethyl)-5-(4-chlorophenyl)-4H-1,2,4-triazol-3-yl)thio)acetic acid (TA-15)

3124 (C-H str.), 1556 (C=C str.), 1783 (C=O str.), 2823 (C-H str., CH2), 1521 (C=N str.), 1382 (C-N str.), 813 (C-S str.), 741 (C-Cl, Ar-Cl str.), 3465 (OH str.)

m/z 329 [M+ +1]

7.33-7.99 (m, 4H, Ar-H) i.e. presence of one phenyl ring and 3.87 (s, 2H, S-CH2) and 4.67 (s, 2H, N-CH2) and 10.89 (s, 1H, OH) i.e. presence of two carboxylic groups; 13H-NMR, ? ppm (DMSO-d6): 34.6, 43.4, 128.5, 128.9, 129.4,130.4, 134.2, 138.3, 149.5, 153.9, 171.0, 174.9

C12H10ClN3O4S: C, 43.98; H, 3.08; N, 12.82; Found: C, 43.92; H, 3.12; N, 12.79

16

1-(4-((4-(4-Acetylphenyl)-5-(3-bromophenyl)-4H-1,2,4-triazol-3-yl)thio)phenyl)ethanone (TA-16)

3132 (C-H str.), 1533 (C=C str.), 1743 (C=O str.), 2872 (C-H str., CH3), 1521 (C=N str.), 1344 (C-N str.), 811 (C-S str.), 643 (Ar-Br str.)

m/z 493[M+ +1]

7.30-8.91 (m, 12H, Ar-H) i.e. presence of three phenyl rings and 2.63{s, 6H, 2-(CH3)2} i.e. presence of two acetyl groups; 13H-NMR, ? ppm (DMSO-d6): 26.3, 122.3, 126.4, 128.7, 128.8, 129.4, 131.2, 132.6, 133.5, 136.2, 137.8, 147.2, 153.5, 160.0, 197.0

C24H18BrN3O2S C, 58.54; H, 3.68; N, 8.53; Found: C, 58.50; H, 3.64; N, 8.58

17

1-(4-Bromophenyl)-2-((5-(3-bromophenyl)-4-(2-(4-bromophenyl)-2-oxoethyl)-4H-1,2,4-triazol-3-yl)thio)ethanone (TA-17)

3123 (C-H str.), 1555 (C=C str.), 1747 (C=O str.), 2822 (C-H str., CH2), 1521 (C=N str.), 1312 (C-N str.), 817 (C-S str.), 646 (Ar-Br str.)

m/z 651[M+ +1]

7.31-7.85 (m, 12H, Ar-H) i.e. presence of three phenyl rings, 4.45 (s, 2H, S-CH2) and 4.80 (s, 2H, N-CH2) i.e. presence of two acetyl groups; 13H-NMR, ? ppm (DMSO-d6): 38.5, 47.2, 122.6, 126.3, 128.8, 129.6, 129.8, 131.8, 132.6, 133.0, 149.2, 153.4, 190.0, 193.0

C24H16Br3N3O2S: C, 44.33; H, 2.48; N, 6.46; Found: C, 44.29; H, 2.46; N, 6.42

18

2-((5-(3-Bromophenyl)-4-(carboxymethyl)-4H-1,2,4-triazol-3-yl)thio)acetic acid (TA-18)

3145 (C-H str.), 1511 (C=C str.), 1742 (C=O str.), 2873 (C-H str., CH2), 1523 (C=N str.), 1344 (C-N str.), 813 (C-S str.), 643 (Ar-Br str.), 3431 (OH str.)

m/z 373[M+ +1]

7.34-7.89 (m, 4H, Ar-H) i.e. presence of one phenyl ring and 4.86 (s, 2H, S-CH2) and 4.45 (s, 2H, N-CH2) and 9.01 (s, 1H, OH) i.e. presence of two carboxylic groups; 13H-NMR, ? ppm (DMSO-d6): 34.9, 43.4, 128.5, 128.9, 131.1, 132.6, 149.5, 153.5, 171.0, 174.3

C12H10BrN3O4S: C, 38.72; H, 2.71; N, 11.29; Found: C, 38.68; H, 2.67; N, 11.25

19

1-(4-((4-(4-Acetylphenyl)-5-(2-iodophenyl)-4H-1,2,4-triazol-3-yl)thio)phenyl)ethanone (TA-19)

3132 (C-H str.), 1534 (C=C str.), 1742 (C=O str.), 2822 (C-H str., CH3), 1521 (C=N str.), 1342 (C-N str.), 823 (C-S str.), 634 (C-I, Ar-I str.)

m/z 540 [M+ +1]

6.99-7.90 (m, 12H, Ar-H) i.e. presence of three phenyl rings and 2.50 (s, 6H, 2-CH3) i.e. presence of two acetyl groups; 13H-NMR, ? ppm (DMSO-d6): 26.8, 95.3, 128.1, 128.8, 129.8, 130.1, 132.6, 133.4, 136.2, 137.8, 147.4, 153.5, 160.2, 196.0

C24H18IN3O2S: C, 53.44; H, 3.36; N, 7.79; Found: C, 53.40; H, 3.32; N, 7.60

20

1-(4-Bromophenyl)-2-((4-(2-(4-bromophenyl)-2-oxoethyl)-5-(2-iodophenyl)-4H-1,2,4-triazol-3-yl)thio)ethanone (TA-20)

3131 (C-H str.), 1532 (C=C str.), 1723 (C=O str.), 2872 (C-H str., CH2), 1522 (C=N str.), 1343 (C-N str.), 813 (C-S str.), 643 (Ar-Br str.), 623 (C-I, Ar-I str.)

m/z 698 [M+ +1]

7.22-8.79 (m, 12H, Ar-H) i.e. presence of three phenyl rings, 4.14 (s, 2H, S-CH2) and 4.78 (s, 2H, N-CH2) i.e. presence of two acetyl groups; 13H-NMR, ? ppm (DMSO-d6): 38.5, 47.2, 95.8, 127.4, 128.8, 129.6, 129.8, 130.3, 131.8, 133.0, 134.4, 149.2, 153.6, 190.8, 194.2

C24H16Br2IN3O2S: C, 41.35; H, 2.31; N, 6.03; Found: C, 41.31; H, 2.36; N, 6.07

21

2-((4-(Carboxymethyl)-5-(2-iodophenyl)-4H-1,2,4-triazol-3-yl)thio)acetic acid (TA-21)

3143 (C-H str.), 1512 (C=C str.), 1752 (C=O str.), 2866 (C-H str., CH2), 1524 (C=N str.), 1344 (C-N str.), 813 (C-S str.), 623 (C-I, Ar-I str.), 3461 (OH str.)

m/z 420 [M+ +1]

6.92-7.70 (m, 4H, Ar-H) i.e. presence of one phenyl ring and 4.87 (s, 2H, S-CH2) and 4.63 (s, 2H, N-CH2) and 10.25 (s, 1H, OH) i.e. presence of two carboxylic groups; 13H-NMR, ? ppm (DMSO-d6): 34.9, 43.4, 95.1, 128.5, 129.2, 130.1, 136.6, 149.5, 153.9, 171.0, 174.7

C12H10IN3O2S: C, 34.38; H, 2.40; N, 10.02; Found: C, 34.42; H, 2.44; N, 10.06

22

1-(4-((4-(4-Acetylphenyl)-5-(4-nitrophenyl)-4H-1,2,4-triazol-3-yl)thio)phenyl)ethanone (TA-22)

3134 (C-H str.), 1536 (C=C str.), 1725 (C=O str.), 2871 (C-H str., CH2), 1521 (C=N str.), 1343 (C-N str.), 817 (C-S str.), 1519 (asym NO2), 1384 (sym NO2)

m/z 459 [M+ +1]

7.20-8.90 (m, 12H, Ar-H) i.e. presence of three phenyl rings and 2.49 {s, 6H, (CH3)2} i.e. presence of two acetyl groups; 13H-NMR, ? ppm (DMSO-d6): 26.8, 124.5, 127.5, 128.1, 128.3, 129.8, 132.1, 132.6, 133.4, 136.2, 137.8, 140.2, 147.4, 153.5, 160.2, 197.0

C24H18N4O4S: C, 62.87; H, 3.96; N, 12.22; Found: C, 62.83; H, 3.92; N, 12.18

23

1-(4-Bromophenyl)-2-((4-(2-(4-bromophenyl)-2-oxoethyl)-5-(4-nitrophenyl)-4H-1,2,4-triazol-3-yl)thio)ethanone (TA-23)

3133 (C-H str.), 1534 (C=C str.), 1723 (C=O str.), 2872 (C-H str., CH2), 1522 (C=N str.), 1344 (C-N str.), 813 (C-S str.), 640 (Ar-Br str.), 1518 (asym NO2), 1334 (sym NO2)

m/z 617 [M+ +1]

7.34-8.78 (m, 12H, Ar-H) i.e. presence of three phenyl rings, 4.19 (s, 2H, S-CH2) and 4.80 (s, 2H, N-CH2) i.e. presence of two acetyl groups; 13H-NMR, ? ppm (DMSO-d6): 38.7, 47.2, 124.5, 127.0, 129.0, 129.8, 130.3, 131.8, 133.3, 134.5, 147.5, 149.7, 153.6, 190.5, 194.2

C24H16Br2N4O4S: C, 46.77; H, 2.62; N, 9.09; Found: C, 46.72; H, 2.68; N, 9.13

24

2-((4-(Carboxymethyl)-5-(4-nitrophenyl)-4H-1,2,4-triazol-3-yl)thio)acetic acid (TA-24)

3135 (C-H str.), 1537 (C=C str.), 1723 (C=O str.), 2876 (C-H str., CH2), 1524 (C=N str.), 1349 (C-N str.), 816 (C-S str.), 3466 (OH str.), 1511 (asym NO2), 1388 (sym NO2)

m/z 339 [M+ +1]

7.30-8.75 (m, 4H, Ar-H) i.e. presence of one phenyl ring and 4.37 (s, 2H, S-CH2) and 4.73 (s, 2H, N-CH2) and 10.22 (s, 1H, OH) i.e. presence of two carboxylic groups; 13H-NMR, ? ppm (DMSO-d6): 34.9, 43.4, 124.5, 127.2, 136.6, 147.6, 149.5, 153.8, 171.0, 174.7

C12H10N4O6S: C, 42.60; H, 2.98; N, 16.56; Found: C, 42.64; H, 2.94; N, 16.60

25

1-(4-((4-(4-Acetylphenyl)-5-((2,4-dichlorophenoxy)methyl)-4H-1,2,4-triazol-3-yl)thio) phenyl)ethanone (TA-25)

3142 (C-H str.), 1564 (C=C str.), 1742 (C=O str.), 2827 (C-H str., CH3), 1511 (C=N str.), 1314 (C-N str.), 814 (C-S str.), 1343 (C-O-C str.), 733 (C-Cl, Ar-Cl str.)

m/z 513 [M+ +1]

6.23-8.75 (m, 11H, Ar-H) i.e. presence of three phenyl rings, 2.67{s, 6H, (CH3)2} i.e. presence of two acetyl groups, 5.45 (s,2H,CH2); 13H-NMR, ? ppm (DMSO-d6): 26.8, 68.4, 117.5, 121.5, 128.5, 128.1, 128.3, 129.8, 131.7, 132.1, 132.6, 133.4, 136.2, 137.8, 149.2, 150.2, 159.5, 197.6, 197.0

C25H19Cl2N3O3S: C, 58.60; H, 3.74; N, 8.20; Found: C, 58.64; H, 3.70; N, 8.16

26

1-(4-Bromophenyl)-2-((4-(2-(4-bromophenyl)-2-oxoethyl)-5-((2,4-dichlorophenoxy)methyl)-4H-1,2,4-triazol-3-yl)thio)ethanone (TA-26)

3154 (C-H str.), 1554 (C=C str.), 1743 (C=O str.), 2837 (C-H str., CH2), 1513 (C=N str.), 1323 (C-N str.), 812 (C-S str.), 1324 (C-O-C str.), 724 (C-Cl, Ar-Cl str.), 634 (C-Br, Ar-Br str.)

m/z 671[M+ +1]

7.11-8.91 (m, 11H, Ar-H) i.e. presence of three phenyl rings and 4.11 (s, 2H, S-CH2) and 4.75 (s, 2H, N-CH2) i.e. presence of two acetyl groups, 5.45 (s,2H,CH2); 13H-NMR, ? ppm (DMSO-d6): 38.7, 47.2, 68.3, 117.6, 121.5, 127.0, 128.5, 129.0, 129.8, 131.8, 133.3, 134.5, 148.5, 152.3, 157.6, 190.5, 194.2

C25H17Br2Cl2N3O3S: C, 44.80; H, 2.56; N, 6.27; Found: C, 44.84; H, 2.60; N, 6.31

27

2-((4-(Carboxymethyl)-5-((2,4-dichlorophenoxy)methyl)-4H-1,2,4-triazol-3-yl)thio)acetic acid (TA-27)

3122 (C-H str.), 1556 (C=C str.), 1782 (C=O str.), 2835 (C-H str., CH2), 1551 (C=N str..), 1383 (C-N str..), 812 (C-S str.), 1312 (C-O-C str.), 732 (C-Cl, Ar-Cl str.), 3462 (OH str.)

m/z 393 [M+ +1]

7.45-7.75 (t, 3H, Ar-H) i.e. presence of three phenyl rings, 4.13 (s, 2H, S-CH2) and 4.54 (s, 2H, N-CH2) i.e. presence of two acetyl groups, 10.11 (s, 1H, OH) i.e. presence of two carboxylic groups; 13H-NMR, ? ppm (DMSO-d6): 34.9, 43.4, 67.3, 117.5, 121.5, 128.5, 129.2, 131.2, 148.7, 152.8, 171.0, 174.7

C13H11Cl2N3O5S: C, 39.81; H, 2.83; N, 10.71; Found: C, 39.85; H, 2.87; N, 10.75

Conclusion

From our present work we conclude that the synthesized 3,4,5-substituted-1,2,4-triazole derivatives showed good antimicrobial and analgesic properties by different technique. Among the series, compounds TA-11, TA-20 and TA-26 displayed more antimicrobial activity than standard drugs cefadroxil (antibacterial) and fluconazole (antifungal) due to presence of electron withdrawing groups. Analgesic study demonstrated that compounds TA-13, TA-15 and TA-2, TA-15 exhibited good analgesic activity by Tail immersion and Acetic acid induced writhing method respectively. The electron withdrawing group plays an important role to enhance the antimicrobial and analgesic activities of the synthesized compounds and these compounds may be used as a lead for discover a new biological agents. 

Author’s declaration

Conflict Of Interest: The author(s) confirms that this article content has no conflicts of interest.

Author's Contributions

PKV- designed and finalized the scheme; DP- performed research work; GS-performed analgesic activity and DP analyzed the spectral and biological data and wrote the paper. All authors read and approved the final manuscript.

Acknowledgement

Thanks to Prof. Munish Garg, Head, Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak for kind support for providing chemicals etc. 

Permission by Institutional Animal Ethics Committee of MDU, Rohtak.

 All the protocol of the animal activity has been approved by Institutional Animal Ethics Committee of M. D. University, Rohtak and some of the compounds synthesized were evaluated for analgesic activity. All the animals were maintained under standard conditions and had access to pelleted animal feed and water.

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CORRESPONDENCE & COPYRIGHT

*Corresponding Author: Dr. Prabhakar Kumar Verma, Associate Professor, Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak, Haryana, 124001, India.

Copyright: © 2021 All copyrights are reserved by Prabhakar Kumar Verma, published by Coalesce Research Group. This work is licensed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited.

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