Abstract

1,3,4-oxadiazoles, heterocycles bearing one oxygen and two nitrogen atoms in a five membered ring have their application in the diverse areas of medicine.[1] This interesting group of compounds has diverse biological activities such as antibacterial, antifungal, antiviral, anticonvulsant, anticancer, anti-inflammatory, anti HIV, anti-tubercular activity etc.[2] Researchers are interested in developing and studying novel heterocyclic compounds that contain 1,3,4-oxadiazole because of its many significant applications. We have attempted to provide an overview of some of the significant studies that have been recognized for the various biological activities exhibited by 1,3,4-oxadiazole derivatives.[3] These findings and our interest in pharmaceutical chemistry of heterocyclic compounds which guide us to synthesize different derivatives of 1,3,4-oxadiazole with different substitution and there pharmacological activities. This article will aid in the development of new compounds that contain 1,3,4-oxadiazole derivatives, which may be essential in the treatment of many illnesses and serve as a model medicine.[4].

Keywords

Introduction

Therefore, 1,3,4-oxadiazoles have attracted the researchers all over the world to work in this area of new drug development. An enormous amount of research was undertaken to synthesize these classes of compounds by employing traditional methods, introducing new innovative methods and techniques, to reach the target molecules and study their biological applications.

BIOLOGICAL ACTIVITY

1.1: Anti Inflammatory Activity:  Biphenyl-4-yloxy acetic acid derivatives 1,3,4-oxadiazole and 1,2,4-triazole [Figure 6] were produced, and their anti-inflammatory properties reduced ulcerogenic potential, analgesic action, and activity. Using the carrageenan-induced rat paw edema test technique, the anti-inflammatory properties of each drug were assessed. The chemical was assessed as the lead compound with a lower ulcerogenic rate, greater anti-potential, and a protective effect on lipid peroxidation. It also had inflammatory activity (81.81%) compared to the reference medication (79.54%).^[8]

Figure 6

1.2: Several derivatives of aroylpropanoic acid with oxadiazole nucleus were produced and tested for anti-inflammatory properties. Studies on analgesic and ulcerogenic properties, as well as lipid peroxidation. Some manufactured compounds were safe and had anti-inflammatory and analgesic properties similar to ibuprofen. The results indicate that the produced chemicals can be employed as safer anti-inflammatory medicines.^[9]

Figure 7

1.3: Some are new. 2-Substituted aryl-5-(2,4,6-trichlorophenoxy methyl)-1,3,4oxadiazoles, [Figure 8] had significant anti-inflammatory activity which inhibit carrageenan-induced rat paw. Compared to the conventional medicine ibuprofen (86.36), edema was reduced by 72.72 percent.^[10]

Figure 8

1.4: Two new series of 1-(4-benzylphenyl)-3-(5-substituted phenyl-[1,3,4]oxadiazole-2-yl].-propan-1-one,[Figure 9] and 1-(4-ethylphenyl).3-(5-substituted phenyl-[1,3,4]oxadiazole-2-yl-Propan-1-one,[Figure 10] was tested for anti-inflammatory properties. The anti-inflammatory action of 4-methoxy and 3,4-dimethoxy phenyls was significantly higher, with 52.6 and 56.2 percentage inhibition, respectively. The reaction against indomethacin was 61%.^[11]

Figure 9

Figure 10

1.5: A novel series of 2-[3-(4-bromophenyl)propan-3-one].-5-(substituted phenyl).-1,3,4-oxadiazoles[Figure 11] were synthesized from 3-(4-bromobenzoyl) propionic. The goal is to develop effective anti-inflammatory and analgesic drugs with minimal or no side effects (ulcerogenicity). Two compounds: 2-[3-(4-bromophenyl)-propan-3-one].-5-(4-chlorophenyl)-1,3,4-oxadiazole and 2-[3-(4-bromophenyl)propan-3-one].The anti-inflammatory activity of -5-(3,4-dimethoxy phenyl)-1,3,4-oxadiazole (59.5 and 61.9%, respectively) was equivalent to that of indomethacin (64.3% at 20 mg kg-1).^[12]

Figure 11

2. Antimicrobial Activity:

2.1: A sequence of biphenyl-1,3,4-oxadiazoles, namely 5-[substituted-(1,10-biphenyl)-3-yl].[Figure 12] The organic synthesis of -1,3,4-oxadiazole-2(3H)-thiones and their S-alkyl derivatives involved multiple steps. Suzuki-Miyaura coupling with palladium catalyst. The compounds were studied using 1H NMR, 13C NMR, 19F NMR, IR, and LCMS spectroscopy. They were investigated for antibacterial and analgesic properties. Some of them had strong activity^[13].

Figure 12

2.2: New 2-substituted [4-(1,3,4-oxadiazol-2yl)methyl]The phthalazin-1(2H)-[Figure 13]one derivatives  were synthesized from methyl (4-oxo-3,4-dihydrophthalazin-1-yl) acetate
was produced using phthalic anhydride. New compounds were produced, described using spectral data, and tested for antibacterial activity against diverse bacteria and fungi. Several of these compounds demonstrated antibacterial action^[14].

Figure 13

2.3: Medicinal chemists will continue to face the challenge of discovering novel antimicrobial drugs. BB-83698 is an antibacterial agent. It is an inhibitor of the metallo enzyme PDF (Peptide). Deformylase). PDF is a promising bacterial target for developing antibiotics with no cross-resistance to existing medicines.

Antimicrobial activity was tested on substituted 5-indole-1,3,4-oxadiazoles. Compound 5-indole-1, 3, 4-oxadiazole demonstrated antibacterial action against B. subtilis and P. aeruginosa (2-). (3-chlorophenyl)-5-indole-1,3,4-oxadiazole[Figure 14] is effective against S. aureus, E. coli, and B. subtilis, while 2-phenyl-5-Indole-1,3,4-Oxadiazole[Figure 15] against S. aureus .The chemical 2-naptho  furan-2-yl-5-(4-methoxy phenyl)l-1,3,4-oxadiazole[Figure 16] showed good action against E. coli, M. luteus, and S. aureus, with zone of inhibitions of and respectively^[15].

Figure 14

Figure 15  

Figure 16

2.4: Novel 3-acetyl-5-(3-chloro-1-benzo[b]thiophen-2-yl)-2-substituted phenyl-2,3-dihydro-1,3,4-oxadiazoles[Figure 17] and 2-(3-chloro-1- We produced and tested benzo[b]thiophen-2-yl)-5-substituted phenyl-1,3,4-oxadiazoles for antibacterial activity. The compounds were tested for antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa, as well as antifungal activity against Candida albicans and Aspergillus niger. The compounds had considerable antibacterial and mild antifungal activity. Compounds were shown to be more effective than ciprofloxacin against S. aureus and B. subtilis^[16].

Figure 17

3: Anti-tumor Activity

3.1: Numerous antitumoral medications are presently being used in clinical settings. Numerous 1,3,4-oxadiazol derivatives were found as a result of the hunt for anticancer medications. possessing antitumoral properties. Numerous antitumoral medications are presently being used in clinical settings. Numerous 1,3,4-oxadiazol derivatives were found as a result of the hunt for anticancer medications. possessing antitumoral properties 1-substituted phenyl-3-[3-alkylamino(methyl)-2-thioxo-1,3,4-oxadiazol-5-yl][Figure 18] is a new series. The most promising compounds were discovered to be ß-carboline derivatives, which showed a broad spectrum of anticancer efficacy at both GI 50 and TGI levels. Their respective GI 50 (MG-MID) values were 5.89, 4.37, and 4.57 µmol l-1. Respectively^[17].

Figure 18

3.2:  2-(2-adamantyl-1,3-thiazol-4-yl)-5-(3-substituted phenyl)[Figure 19] is a novel family of adamantanyl-1,3-thiazole and 1,3,4-oxadiazole derivatives. A wide panel of human tumor-derived cell lines was used to test the in-vitro anti proliferative efficacy of -1,3,4-oxadiazole with different aryl groups^[18].

Figure 19

3.3: sequence of five or seven substitutes 3-{4-(5-mercapto}1,3,4-oxadiazol-2-yl)phenylimino}In order to create -indolin-2-one derivatives, 5-(4-aminophenyl)Oxadiazole-2-thiol-1,3,4 [Figure 20]with distinct derivatives of isatin. Using the MTT assay, all of the produced derivatives were examined for anticancer efficacy against HeLa cancer cell lines. Every synthesized chemical inhibited cell growth in a dose-dependent manner. All of the synthetic test substances' IC50 values were between 10.64 and 33.62_M. Compound VIb-d's anticancer activity potency (IC50 values) was similar to that of cisplatin, a well-known anticancer drug. The compounds VI b-d containing the halogen atom (an electron withdrawing group) at the C5 position exhibited the most activity among the produced 2-indolinones^[19].

Figure 20

4. Anti-Oxidant

1,3,4-oxadiazole nucleus are known to exhibit potential antioxidant activity.The search for antioxidant drugs led to the discovery of several 1,3,4-oxadiazol  derivatives having antioxidant activity.

4.1: 5-pyridyl-2-[(N-substituted phenyl)thioacetamido]-1,3,4-oxadiazoles [Figure 21]were synthesized using traditional and microwave techniques, and their in vitro antioxidant activity was assessed using 1,1-diphenyl-2,2-picryl method of hydrazyl free radicals. At a lower concentration, the molecule with 2-chloro substitution has suppressed the DPPH radical^[20].

Figure 21

4.2: The antioxidant activity of  new 3-acetyl-2-(substituted phenyl)-5-(4-methylcoumarinyl-7-oxymethyl)-2,3-dihydro 1,3,4-oxadiazoles[Figure 22] was assessed. The diphenylpicryl hydrazyl demonstrated over 50% antioxidant activity in the derivatives with the H, CH3 group as anti oxidant^[21] .

Figure 22

5. Analgesic Activity:

In the acetic acid-induced writhing test, a novel series of 1-(4-phenoxyphenyl)-3-[5-(substituted aryl)-1,3,4-oxadiazol2-yl]propan-1-ones [Figure 23], 16 derivatives demonstrated notable analgesic effect. In terms of analgesic action, the 2-acetoxy phenyl derivative of this series has demonstrated 76% protection, which is significantly better than the common medication indomethacin^[22]

Figure 23

6. ANTIDIABETIC

When looking for benzimidazole derivatives with broad range pharmacological activity, a class of 4-thiazolidinones  and 1,3,4-oxadiazoles [Figure 24]  were created and tested for antidiabetic activity using the Oral Glucose Tolerance Test (OGTT) and in vivo anticonvulsant activity using the Maximal Electroshock (MES) paradigm^[23].

Figure 24

7. ANTI ALZIMER ACTIVITY

A number of derivatives of 2,5-diphenyl-1,3,4-oxadiazole [Figure 25]are used to identify b-amyloid plaques in Alzheimer's disease brains. The inclination towards amyloid plaques was evaluated utilizing preformed synthetic Ab42 aggregates in an in vitro binding test. With Ki values ranging from 20 to 349 nM, the novel class of 1,3,4-DPOD derivatives demonstrated affinity for Ab42aggregates.
In an animal model of Alzheimer's disease, the 1,3,4-DPOD derivatives clearly stained b-amyloid plaques, demonstrating their in vitro affinity for Ab42 aggregates.
In biodistribution studies employing normal mice, they demonstrated superior brain penetration and rapid brain washout in comparison to 3,5-diphenyl-1,2,4-oxadiazole (1,2,4-DPOD) derivatives. The new radioiodinated 1,3,4-DPOD derivatives could be helpful markers for identifying Alzheimer's disease-related b-amyloid plaques^[24].

Figure 25

8. CALSIUM-CHANNEL BLOCKER:

In the present study, we investigated whether the correction of endothelial dysfunction is dependent on the normalization of high blood pressure levels by
1,3,4-oxadiazole derivative (NOX-1) in hypertensive rats treated with NG-nitro-l-arginine (L-NNA) and deoxycorticosterone acetate (DOCA-salt). The mean systolic blood pressure (MSBB) in DOCA-salt and L-NNA hypertensive rats was 185.3±4.7 and 170.2±4.1 mmHg, respectively. However, following NOX-1 injection, the MSBB in hypertensive rats was 127.8±4.5 and 120.2±5.1 mmHg.^[25]  [Figure 26]

Figure 26

9.Anthelmintic Activity:

The anthelmintic activity of derivatives of a novel series of 1-[(5-substituted-1,3,4-oxadiazol-2-yl)-methyl]-4-propylpiperazines was assessed^[26].[ Figure 27]

Figure 27

At a dosage of 2 mg/ml, it was discovered that the 2-furyl, 3-pyridyl, and p-methyl phenoxy derivatives were more effective against the earth worms Eudrilus species, Megascoplex konkanensis, and Pontoscotex corethruses.

10. Antiviral Activity

One of the first illnesses for which the complete drug discovery process was conducted using a logical drug design methodology was HIV infection and AIDS. When tested against the human immunodeficiency virus (HIV-1), novel 2-{5-[(naphthalen-5-yloxy)methyl]-1,3,4-oxadiazol-2-ylthio} acetohydrazones 37 shown moderate to strong antiviral activity^[27].

11. Anticonvulsant Activity

The neurological condition known as epilepsy is characterized by abnormal, sporadic, and spontaneous electrical activity in the brain. Despite the fact that new antiepileptic medications have been available for use in clinical settings for the past 20 years, the maximum electroshock (MES) test and the subcutaneous pentylenetetrazole (scPTZ) test are the most popular epilepsy models used to describe the anticonvulsant properties.

11.1: Phenyl-4,5-dihydro-1,3,4-oxadiazol-2-yl)-2Hchromene-2-ones,[ Figure 28]  series of 3-(4-acetyl-5-methyl-5-substituted the neurotoxicity and anticonvulsant properties of 3-(4-acetyl-5H-5-substituted phenyl4,5-dihydro-1,3,4-oxadiazol-2-yl)-2Hchromene-2-ones were assessed. [Figure 29] 3-(4-Acetyl-5-In the MES-test, methyl-5-p-nitrophenyl-4,5-dihydro-1,3,4-oxadiazol-2-yl)-2H-chromen-2-one shown strong activity at a lower dose of 30 mg/kg and was less hazardous than the conventional medication phenytoin^[28].

Figure 28 

       Figure 29

11.2: novel 2-substituted-5-{2-[(2-halobenzyl)thio)phenyl}-1,3,4- oxadiazoles [Figure 30] were created, manufactured, and their anticonvulsant properties were examined. The primary essential pharmacophore is present in the proposed compounds. for attaching itself to the receptors for benzodiazepines. In PTZ and MES models, 5-{2-[(2-fluorobenzyl)thio]phenyl}-1,3,4-oxadiazol-2-amine exhibited strong anticonvulsant effect, according to electroshock and pentylenetetrazole-induced lethal convulsion tests^[29]

Figure 30

12. ACTIVITY ON SKIN:

There have been reports of tyrosinase inhibition investigations of a library of 2,5-disubstituted-1,3,4-oxadiazoles, as well as their structure–activity relationship (SAR)been talked about. This molecule may be the most promising lead compound for future therapeutic development aimed at treating a number of skin conditions.

A set of substituted hydrazides, 4-amino-1,2,4-triazole-5(4H)-thiones, [Figure 31] 1,3,4-thiadiazole-2(3H)-thiones, [Figure 32 ] and 1,3,4-oxadiazole-2(3H)-thiones [Figure 33]were created and modified to become new, powerful tyrosinase inhibitors^[30].

Figure 31

Figure 32

Figure 33

13. MAO INHIBITOR

13.1 The inhibitory effects of eighteen novel 5-aryl-1,3,4-oxadiazol-2(3H)-one [Figure 34]derivatives and sulfur analogues were assessed in vitro. Types A and B of monoamine oxidase (MAO). The most potent substances in these series had I&a values between 1.8 and 0.056 PM, indicating a selective action against MAO B. The oxadiazole thione analogue  and 5-(4-biphenylyl)-3-(2-cyanoethyl)-1,3,4-oxadiazol-2(3H)-one were discovered to function as strong, competitive, and selective MAO B inhibitors with a somewhat slow-binding nature^[31].

Figure 34

13.2 A new series of 1,3,4-oxadiazole-3(2H)-carboxamide[ Figure 35] derivatives were produced through the direct heterocyclization reaction of substituted benzoylisocyanate with different roylhydrazones. Novel monoamine oxidase inhibitors (MAOIs). This study suggests a new class of lead compounds with potential MAO inhibitors for future improvement^[32].

Figure 35

14. Herbicidal activity

Oxadiazon of 3-[2,4-dichloro-5-(1-methylethoxy)phenyl]-5-(1,1-dimethylethyl )-1,3,4-oxadiazol-2(3H)32 belongs to the oxadiazole category of herbicides. To manage weed resistance, the product is a group G herbicide.  Oxadiargyl (TOPSTAR 80 WP), 3.-[2,4-dichlorophenyl -5-(2-propynyloxy)-5-(1,1-dimethylethyl)-1,3,4-oxadiazol-2(3H)One, 33 is a broad-spectrum weed control with recognized international registrations^[33].

CONCLUSION

This article provides an overview of the medicinal and biological properties of the 1,3,4-oxadiazole ring, as well as available medications containing the heterocyclic ring. The comprehensive review highlights the therapeutic potential of 1,3,4-oxadiazole derivatives for central nervous system disorders, pain relief, and inflammation reduction. These results have guided the development of the 1,3,4-oxadiazole nucleus, which has the potential to Lead nucleus for future research to produce safer and more effective chemicals. This paper has major implications for future research on the bioactive oxadiazole ring.

ACKNOWLEDGEMENT

Author expresses her due thanks to Priyadarshini J.L College of Pharmacy Nagpur, Maharashtra.

REFERENCES

1. Redhu S, Kharb R. Recent updates on chemistry and pharmacological aspects of 1, 3, 4-oxadiazole scaffold. Int J Pharm Innov. 2013;3(1):93-110.
2. Bala S, Kamboj S, Kumar A. Heterocyclic 1, 3, 4-oxadiazole compounds with diverse biological activities: A comprehensive review. J. Pharm. Res. 2010 Sep 13;3(12):2993-7.
3. Kumar KA, Lokeshwari DM, Pavithra G, Kumar GV. 1, 2, 4-Oxadiazoles: A potential pharmacological agents-An overview. Research Journal of Pharmacy and Technology. 2012;5(12):1490-6.
4. Husain A, Ajmal M. Synthesis of novel 1, 3, 4-oxadiazole derivatives and their biological properties. Acta pharmaceutica. 2009 Jun 1;59(2):223-33.
5. Kumar KA, Jayaroopa P, Kumar GV. Comprehensive review on the chemistry of 1, 3, 4-oxadiazoles and their applications. Int. J. Chem. Tech. Res. 2012;4(4):1782-91.
6. Patel KD, Prajapati SM, Panchal SN, Patel HD. Review of synthesis of 1, 3, 4-oxadiazole derivatives. Synthetic Communications. 2014 Jul 3;44(13):1859-75.
7. Redhu S, Kharb R. Recent updates on chemistry and pharmacological aspects of 1, 3, 4-oxadiazole scaffold. Int J Pharm Innov. 2013;3(1):93-110.
8. Burbuliene MM, Jakubkiene V, Mekuskiene G, Udrenaite E, Smicius R, Vainilavicius P. Synthesis and anti-inflammatory activity of derivatives of 5-[(2-disubstitutedamino-6-methyl-pyrimidin-4-yl)-sulfanylmethyl]-3H-1, 3, 4-oxadiazole-2-thiones. Il Farmaco. 2004 Oct 1;59(10):767-74.
9. Akhter M, Husain A, Azad B, Ajmal M. Aroylpropionic acid based 2, 5-disubstituted-1, 3, 4-oxadiazoles: Synthesis and their anti-inflammatory and analgesic activities. European journal of medicinal chemistry. 2009 Jun 1;44(6):2372-8.
10. Amir M, Javed SA, Kumar H. Synthesis of some 1, 3, 4-oxadiazole derivatives as potential anti-inflammatory agents.
11. Husain A, Ahuja P. Synthesis and biological evaluation of ?-aroylpropionic acid based 1, 3, 4-oxadiazoles. Indian journal of pharmaceutical sciences. 2009 Jan;71(1):62.
12. Burbuliene MM, Jakubkiene V, Mekuskiene G, Udrenaite E, Smicius R, Vainilavicius P. Synthesis and anti-inflammatory activity of derivatives of 5-[(2-disubstitutedamino-6-methyl-pyrimidin-4-yl)-sulfanylmethyl]-3H-1, 3, 4-oxadiazole-2-thiones. Il Farmaco. 2004 Oct 1;59(10):767-74.
13. Burbuliene MM, Jakubkiene V, Mekuskiene G, Udrenaite E, Smicius R, Vainilavicius P. Synthesis and anti-inflammatory activity of derivatives of 5-[(2-disubstitutedamino-6-methyl-pyrimidin-4-yl)-sulfanylmethyl]-3H-1, 3, 4-oxadiazole-2-thiones. Il Farmaco. 2004 Oct 1;59(10):767-74.
14. Bakht MA, Yar MS, Abdel-Hamid SG, Al Qasoumi SI, Samad A. Molecular properties prediction, synthesis and antimicrobial activity of some newer oxadiazole derivatives. European journal of medicinal chemistry. 2010 Dec 1;45(12):5862-9.
15. Bhardwaj N, Saraf SK, Sharma P, Kumar P. Syntheses, Evaluation and Characterization of Some 1, 3, 4?Oxadiazoles as Antimicrobial Agents. Journal of Chemistry. 2009;6(4):1133-8.
16. Ansari KF, Lal C. Synthesis, physicochemical properties and antimicrobial activity of some new benzimidazole derivatives. European journal of medicinal chemistry. 2009 Oct 1;44(10):4028-33.
17. Savariz FC, Formagio AS, Barbosa VA, Foglio MA, Carvalho JE, Duarte MC, Dias Filho BP, Sarragiotto MH. Synthesis, antitumor and antimicrobial activity of novel 1-substituted phenyl-3-[3-alkylamino (methyl)-2-thioxo-1, 3, 4-oxadiazol-5-yl] ?-carboline derivatives. Journal of the Brazilian Chemical Society. 2010;21:288-98.
18. Zahid M, Yasin KA, Akhtar T, Rama NH, Hameed S, Al-Masoudi NA, Loddo R, La Colla P. Synthesis and in vitro antiproliferative activity of new adamantylthiazolyl-1, 3, 4-oxadiazoles. Arkivoc. 2009 Jan 1;11:85-93.
19. Gudipati R, Anreddy RN, Manda S. Synthesis, characterization and anticancer activity of certain 3-{4-(5-mercapto-1, 3, 4-oxadiazole-2-yl) phenylimino} indolin-2-one derivatives. Saudi Pharmaceutical Journal. 2011 Jul 1;19(3):153-8.
20. Maheshwari R, Chawla P, Saraf SA. Comparison between antioxidant activity of 2, 5-disubstituted 1, 3, 4-oxadiazoles containing heteroaromatic ring and aromatic ring at 2nd position. Medicinal Chemistry Research. 2011 Dec;20:1650-5.
21. Manojkumar P, Ravi TK, GOPALAKRISHNAN G. Synthesis of coumarin heterocyclic derivatives with antioxidant activity and in vitro cytotoxic activity against tumour cells. Acta Pharmaceutica. 2009 Jun 1;59(2):159-68.
22. Husain A, Ahmad FJ, Ajmal M, Ahuja P. Synthesis of 1-(4-phenoxyphenyl)-3-[5-(substituted aryl)-1, 3, 4-oxadiazol-2-yl] propan-1-ones as safer anti-inflammatory and analgesic agents. Journal of the Serbian Chemical Society. 2008;73(8-9):781-91..
23. Ke S, Li Z, Qian X. 1, 3, 4-Oxadiazole-3 (2H)-carboxamide derivatives as potential novel class of monoamine oxidase (MAO) inhibitors: Synthesis, evaluation, and role of urea moiety. Bioorganic & medicinal chemistry. 2008 Aug 15;16(16):7565-72.
24. Saitoh M, Kunitomo J, Kimura E, Hayase Y, Kobayashi H, Uchiyama N, Kawamoto T, Tanaka T, Mol CD, Dougan DR, Textor GS. Design, synthesis and structure–activity relationships of 1, 3, 4-oxadiazole derivatives as novel inhibitors of glycogen synthase kinase-3?. Bioorganic & medicinal chemistry. 2009 Mar 1;17(5):2017-29.
25. Bankar GR, Nampurath GK, Nayak PG, Bhattacharya S. A possible correlation between the correction of endothelial dysfunction and normalization of high blood pressure levels by 1, 3, 4-oxadiazole derivative, an L-type Ca2+ channel blocker in deoxycorticosterone acetate and NG-nitro-l-arginine hypertensive rats. Chemico-biological interactions. 2010 Jan 27;183(2):327-31.
26. Srinivas, K. and Kumar, K.P., 2010. Synthesis, antimicrobial and anthelmintic activity of 1-[(5-sustituted-1, 3, 4-oxadiazol-2-yl) methyl]-4-propylpiperazines. International Journal of Biopharmaceutics, 1(1), pp.14-19.
27. El-Sayed WA, El-Essawy FA, Ali OM, Nasr BS, Abdalla MM, Abdel-Rahman AA. Anti-HIV activity of new substituted 1, 3, 4-oxadiazole derivatives and their acyclic nucleoside analogues. Zeitschrift für Naturforschung C. 2009 Dec 1;64(11-12):773-8.
28. Bhat MA, Siddiqui N, Khan SA. Synthesis of novel 3-(4-acetyl-5H/methyl-5-substituted phenyl-4, 5-dihydro-1, 3, 4-oxadiazol-2-yl)-2H-chromen-2-ones as potential anticonvulsant agents. Acta Pol Pharm. 2008 Mar 1;65(2):235-9.
29. Bhat MA, Siddiqui N, Khan SA. Synthesis of novel 3-(4-acetyl-5H/methyl-5-substituted phenyl-4, 5-dihydro-1, 3, 4-oxadiazol-2-yl)-2H-chromen-2-ones as potential anticonvulsant agents. Acta Pol Pharm. 2008 Mar 1;65(2):235-9.
30. Khan MT, Choudhary MI, Khan KM, Rani M. Structure–activity relationships of tyrosinase inhibitory combinatorial library of 2, 5-disubstituted-1, 3, 4-oxadiazole analogues. Bioorganic & medicinal chemistry. 2005 May 16;13(10):3385-95.
31. Watanabe H, Ono M, Ikeoka R, Haratake M, Saji H, Nakayama M. Synthesis and biological evaluation of radioiodinated 2, 5-diphenyl-1, 3, 4-oxadiazoles for detecting ?-amyloid plaques in the brain. Bioorganic & medicinal chemistry. 2009 Sep 1;17(17):6402-6.
32. Mazouz F, Lebreton L, Milcent R, Burstein C. 5-Aryl-1, 3, 4-oxadiazol-2 (3H)-one derivatives and sulfur analogues as new selective and competitive monoamine oxidase type B inhibitors. European Journal of Medicinal Chemistry. 1990 Oct 1;25(8):659-71.
33. Nandihalli UB, Duke SO. The porphyrin pathway as a herbicide target site.