Synthesis and Evaluation of Antiinflammatory, Analgesic and Ulcerogenic Potential of NSAIDs Bearing 1,3,4-Oxadiazole Scaffold

Synthesis of 1,3,4-oxadiazole derivatives of diclofenac and mefenamic acid are described. The target compounds 5-[2-(2,6-dichloroanilino)benzyl]-2-aryl-1,3,4-oxadiazole (3a-3e) and 5-[2-(2,3-dimethylanilino)phenyl]-2-(aryl)-1,3,4-oxadiazole (6a-6e) were obtained by treating 2 and 5 with various aromatic acids using POCl₃ as dehydrating agent. They were purified and characterized by IR, ¹H-NMR and elemental analysis. These compounds were further subjected to antiinflammatory, analgesic and acute ulcerogenic activity. Compound 3c and 6d exhibited good antiinflammatory activity and compounds 3c, 3e, 6c, 6d, 6e were found to be non ulcerogenic.     

Synthesis of some novel azo derivatives of 3,5-dimethyl-1-(2-hydroxyethyl)pyrazole as potent analgesic agents

A series of 1-(2-hydroxyethyl)-3,5-dimethylpyrazolylazo derivatives, incorporating thiosemicarbazide 2a-c, 1,3,4-thiadiazole 3a-c, and 1,2,4-triazole-3-thione 4a-c were synthesized. The structure of these novel synthesized compounds 2a-c, 3a-c, and 4a-c was confirmed by spectral analysis. All these compounds were screened for their analgesic activity. Hot-plate and tail-immersion tests were used for the determination of the analgesic activity. Morphine, an analgesic through both spinal and supraspinal pathways, was used as a standard test drug. All compounds were administered at a dose of 100 mg/kg i.p. Among the compounds, 2-(butylamino)-5-[((1-(2-hydroxyethyl)-3,5-dimethylpyrazole-4-yl)azo)phenyl]-1,3,4-thiadiazole 3a and 4-[((1-(2-hydroxyethyl)-3,5-dimethylpyrazole-4-yl)azo)phenyl]-4-(2-phenethyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione 4c showed analgesic effects in both tests. Especially 4c exerted strong analgesia starting at 30 min after injection.     

Reaktionen von 2-Amino-imidazo[2,1-b]-1,3,4-thiadiazolen mit Dicarbonsäureestern in Polyphosphorsäure (PPA)

Reactions of 2-Aminoimidazo[2,1-b]-1,3,4-thiazoles with Ethyl Dicarboxylates in Polyphosphoric Acid (PPA) The 2-amino-6-arylimidazo[2,1-b]-1,3,4-thiadiazoles 1d,e cyclise on heating in polyphosphoric acid (PPA) with ethyl malonate or ethyl diethylmalonate to yield the 2-aryl-6,8-dioxodihydro-6H-imidazo[2,1-b]-1,3,4-thiadiazolo[3,2-a] pyrimidines 3d,e or the 7,7-diethyl compounds 4d,e . Compounds 1a – f cyclise in PPA with ethyl succinate or ethyl phthalate to yield the 6-aryl-2-succinimido- or 6-aryl-2-phthalimido-imidazo[2,1-b]-1,3,4-thiadiazoles 5a, b, d-f and 6a – f . Compounds 1d,e were condensed with ethyl oxalate to yield the 2-(ethoxycarbonyl-formylamino)-6-arylimidazo[2,1-b]-1,3,4-thiadiazoles 7d,e. Ethyl levulinate with 1d,e in PPA probably forms 6-aryl-2-(2-methyl-5-oxo-Δ³-pyrrolino)imidazo [2,1-b]-1,3,4-thiadiazoles.     

Design and one-pot and microwave-assisted synthesis of 2-amino/5-aryl-1,3,4-oxadiazoles bearing a benzimidazole moiety as antioxidants

In this study, two new series of 2-amino-1,3,4-oxadiazoles and 5-aryl-1,3,4-oxadiazoles carrying a benzimidazole moiety were synthesized. The antioxidant properties of these compounds were investigated in vitro by the determination of the microsomal NADPH-dependent inhibition of lipid peroxidation levels (LP), the microsomal ethoxyresorufin O-deethylase activity (EROD), and DPPH radical scavenger effects. Among the tested compounds, 2-[(2-(4-chlorophenyl)-1H-benzo[d]imidazole-1-yl)methyl]-5-(4-fluorophenyl)-1,3,4-oxadiazole (9) was found to be the most active compound in all three in vitro systems.     

Synthesis of 3-(3,4-dimethoxyphenyl)-1 H-1,2,4-triazole-5-thiol and 2-amino-5-(3,4-dimethoxyphenyl)-1,3,4-thiadiazole derivatives exhibiting anti-inflammatory activity

New 1-acylderivatives of 5-alkylthio-3-(3,4-dimethoxyphenyl)-4H-1,2,4-triazole (5c-f, 6d-f) were synthesized by the acylation of 5-alkylthio-3-(3,4-dimethoxyphenyl)-4H-1,2,4-triazoles (3, 4) with acyl chlorides. The compounds 3, 4 were obtained by the alkylation of 3-(3,4-dimethoxyphenyl)-1H-1,2,4-triazole-5-thiol (2) sodium salt with alkyl iodides. Compound 2 and 2-amino-5-(3,4-dimethoxyphenyl)-1,3,4-thiadiazole (8) were prepared by the treatment of 3,4-dimethoxybenzoylthiosemicarbazide (1) with sodium hydroxide or acetyl chloride (and then sodium hydroxide), respectively. Related 2-acylamino-5-(3,4-dimethoxyphenyl)-1,3,4-thiadiazoles (7c, e, f) were synthesized by the acylation of compound 8 with acyl chlorides. 3-(3,4-Dimethoxyphenyl)-4-phenyl-4,5-dihydro-1H-1,2,4-triazole-5-thione (9) was N-acylated with acyl chlorides or S-methylated with iodomethane to give 1-acyl-3-(3,4-dimethoxyphenyl)-4-phenyl-4,5-dihydro-1H- 1,2,4-triazole-5-thiones (10a, b) or 3-(3,4-dimethoxyphenyl)-5-methylthio-4-phenyl-4H-1,2,4-triazole (11) respectively. The synthesized compounds 6d, 7a, c, 10a, b, 11 exhibit anti-inflammatory activity.     

1-芳基-4-乙氧羰基-5-氨基-1,2,3,-连三唑和几种亲电子试剂的反应及产物抗菌性能的研究

本文研究1-芳基-4-乙氧羰基-5-氨基-1,2,3,-连三唑(1)同过量乙酸,乙酸酐、乙酰氯、苯甲酰氯以及甲酰胺等的反应,制得1的14种新衍生物:1-H-4-乙氧羰基-5-芳胺基-1,2,3-连三唑(2 b～d),1-酰基-4-乙氧羰基-5-芳胺基-1,2,3-连三唑(3a～d),1-芳基-4-乙氧羰基-5-乙酰胺基-1,2,3-连三唑-(4a～d)以及1-甲酰基-4-乙氧羰基-5-对硝基苯胺基-1,2,3-连三唑(5a),1-苯甲酰基-4-乙氧羰基-5-对硝基苯胺基-1,2,3-连三唑(5b),1-对氨苯甲酰基-4-乙氧羰基-5-对硝基苯胺基-1,2,3-连三唑(5c)。所有化合物的结构,均经元素分析及波谱分析确证,并筛选了一些化合物的抗菌作用。     

Synthesis of some new 2-(6-methoxy-2-naphthyl)- 5-aryl-1,3,4-oxadiazoles as possible non-steroidal anti-inflammatory and analgesic agents

The synthesis of some new 2-(6-methoxy-2-naphthyl)-5-aryl-1,3,4-oxadiazoles (4a-k) has been described. Ethyl-6-methoxy-2-naphthoate (1) yielded on treatment with hydrazine hydrate to 6-methoxy-2-naphthoic acid hydrazide (2). Compound 2 reacted with substituted aromatic carboxylic acids (3a-k) in phosphorus oxychloride yielded 2-(6-methoxy-2-naphthyl)-5-aryl-1,3,4-oxadiazoles (4a-k). Newly synthesized compounds were characterized by IR, (1)H-NMR and mass spectral data. All the compounds were screened for their anti-inflammatory and analgesic activity. Compound 4j exhibited promising anti-inflammatory and analgesic activities.     

Synthesis and anticonvulsant activity of novel and potent 2,3-benzodiazepine AMPA/kainate receptor antagonists.

We have previously shown that 1-aryl-3,5-dihydro-7, 8-methylenedioxy-4H-2,3-benzodiazepin-4-ones (3) possess marked anticonvulsant properties and antagonize seizures induced by 2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) in analogy to the structurally related 1-(4-aminophenyl)-4-methyl-7, 8-methylenedioxy-5H-2,3-benzodiazepine (1, GYKI 52466), a well-known noncompetitive AMPA/kainate receptor antagonist. We now report the synthesis of 3-(N-alkylcarbamoyl)-1-aryl-3,5-dihydro-7, 8-methylenedioxy-4H-2,3-benzodiazepin-4-ones (4a-h) and 1-aryl-3, 5-dihydro-7,8-methylenedioxy-4H-2,3-benzodiazepine-4-thiones (5a-c). The activity of all compounds, intraperitoneally (ip) injected, was evaluated against audiogenic seizures in DBA/2 mice and against seizures induced by maximal electroshock (MES) and pentylenetetrazole (PTZ) in Swiss mice. Some of the new compounds 4 and 5 showed remarkable anticonvulsant activity, and their toxicity, as evidenced by the rotarod test, is lower than that of 1. The time course of anticonvulsant activity of derivatives 4b and 5b,c was studied and compared to that of 1 and 3b,c. Compounds 4a,b and 5a-c antagonize seizures induced by AMPA and kainate (KA) and their anticonvulsant activity is reversed by pretreatment with aniracetam. Using the patch-clamp technique, the capability of derivatives 3c, 4b, and 5c to antagonize KA-evoked currents in primary cultures of granule neurons was tested and compared with that of the parent compounds 1 and 1-(4-aminophenyl)-3, 4-dihydro-4-methyl-3-methylcarbamoyl-7,8-methylenedioxy-5H-2, 3-benzodiazepine (2, GYKI 53655).     

Synthesis of some halogen-containing 1,2,4-triazolo-1,3,4-thiadiazines and their antibacterial and anticancer screening studies--part I

A series of 7-arylidene-6-(2,4-dichloro-5-fluorophenyl)-3-substituted-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazines (3) were prepared by the condensation of 4-amino-5-mercapto-3-substituted-1,2,4-triazoles (1) and 3-aryl-1-(2,4-dichloro-5-fluorophenyl)-2-bromo-2-propen-1-one (2). An alternative route for the synthesis of the title compound 3 has been described. The newly synthesised compounds were characterised on the basis of N-analyses, IR, 1H NMR and mass spectral data. Some of the newly synthesised compounds were tested for their antibacterial activities against Gram + ve and Gram - ve bacteria. Among the tested compounds 3n showed the highest degree of antibacterial activity against S. aureus and evaluation of the LD50 value of this compound was carried out. Some of the newly synthesised compounds were also screened for their anticancer activities. Among these, compounds 3b, 3g, 3n and 3p are found to be active against NCI-H460 (lung), MCF7 (breast), SF 268 (CNS) in the preliminary anticancer screening studies. Further, 60-cell-line anticancer studies of these compounds were carried out. The results of such studies are discussed in this paper.     

Antihypertensive thiadiazoles. 1. Synthesis of some 2-aryl-5-hydrazino-1,3,4-thiadiazoles with vasodilator activity

Some 2-aryl-5-hydrazino-1,3,4-thiadiazoles have been synthesized and screened for antihypertensive activity. In general, compounds with a 2-substituted phenyl ring had higher activity than their 3- or 4-substituted counterparts or those containing heteroaryl groups. The 2-methylphenyl and 2-ethylphenyl derivatives 7 and 18 were the most potent members of the series. Preliminary studies indicated that the hypotensive action of these compounds was due to a direct relaxant effect on vascular smooth muscle.     

Microwave assisted synthesis and biological activity of novel coumarinyltriazolothiadiazoles

A series of new 3-(4-methylcoumarinyl-7-oxymethyl)-6-substitutedphenyl-5,6-dihydro-s-triazolo (3,4-b)(1,3,4)-thiadiazoles 2(a-j) have been synthesized by reacting 5-(4-methyl coumarinyl-7-oxymethyl)-4-amino-3-mercapto(4H)-1,2,4-triazole with various aromatic aldehydes by microwave assisted organic synthesis. The structure of the compounds 2 (a-j) has been confirmed by IR, (1)H NMR and mass spectral data. All the compounds were screened for antimicrobial and antioxidant activity. Among the compounds tested, compounds 2d (4-dimethyl amino phenyl derivative) and 2h (3,4-dimethoxy phenyl derivative) showed better antimicrobial and antioxidant activity than rest of the compounds in the series.     

Synthesis of some 1.3.4-thiadiazoles of possible antimicrobial activity

Different new esters of 5-aryl-1,3,4-thiadiazol-2-ylcarbazic acid and dithiocarbazic acid were prepared. In addition, the synthesis of 2-(N,N'-dialkylcarboxy)hydrazino-5-aryl-1,3,4-thiadiazoles is described. IR and NMR data of the new compounds are discussed. Some of these compounds showed a reasonable activity against Gram positive bacteria and fungi.     

Reactivity of 3-aryl-4-amino-5-mercapto-4H-1,2,4-triazoles: synthesis and biological evaluation of 3,6-diaryl derivatives of 7H-1,2,4-thiazole[3,4-b][1,3,4]thiadiazines, of 3-aryl-4-amino-5-carboxymethylthio-4H-1,2,4-triazoles

Starting from 3-aryl-4-amino-5-mercapto-4H-1,2,4-triazoles (II), two series of 3,6-disubstituted 7H-1,2,4-triazol [3,4-b] [1,3,4] thiadiazines (III) and their 5-carboxymethylthio derivatives (IV) were prepared. From the mercapto-amino-triazoles (II) because of their reactivity in some oxidising media, were obtained the triazole derivatives (V), (VI) and (VII). The synthesis of the alpha-thioketones (VIII) of 3-aryl-5-mercapto-1,3,4-oxadiazoles (I), used in alternative synthesis of triazole-thiadiazines (III), is also reported. All the substances described were subjected to biological screening. In the tests, the carboxymethylthiotriazole (IV) showed weak antiinflammatory activity (carrageenin edema) and more consistent scavanger activity, in vitro, on superoxide anions. The triazole-thiadiazines (III) and triazoles (II), (V) and (VI) showed moderate antimycotic activity.     

Coumarin congeners as antidepressants.

3-Carboethyl coumarin (I) was converted to coumarin 3-acid hydrazide (II). This on reaction with appropriate aldehyde yielded 3-arylidino amino coumarin (III). Compound III on diazotisation and reaction with ferric chloride yielded the corresponding formazans viz. 3-substituted phenyl azoarylidino, amido coumarins (IVa1-a10) and oxadiazoles viz. 2-aryl-5-(3-coumarinyl)-1,3,4-oxadiazoles (Va1-a3), respectively. Simultaneously 3-carboethyl coumarin on hydrolysis gave 3-carboxy coumarin (VI) which on reaction with aryl amine in methylene chloride yielded 3-(N-aryl)amido coumarin (VIIa1-a3). The compounds were screened for their antidepressant activity against a tricyclic antidepressant (imipramine). Compounds IVa4, IVa5 and IVa9 exhibited activity better than imipramine with no toxicity (ALD50 greater than 1000 mg/kg) but IVa5 showed some side effects.     

Antilipidemic agents, Part. IV: Synthesis and antilipidemic testing of some heterocyclic derivatives of hexadecyl and cyclohexyl hemisuccinate esters

Two main classes of novel esters containing a hexadecyl or cyclohexyl group and various heterocyclic rings, like quinazolines, triazoles, thiadiazoles and pyrazoles have been synthesized. The first class involves the synthesis of the hexadecyl ester derivatives; namely 3-substituted-2-(hexadecyloxycarbonylpropionylthio)-4(3H)-quinazol inones 4a-c; 4-substituted-3-(4-pyridyl)-5-(hexadecyloxycarbonylpropionylthio)- 4H- 1,2,4-triazoles 6a-c; 5-substituted-2-(hexadecyloxycarbonylpropionylamino)-1,3,4-thiadia zoles 8a-c, 4-[4-(hexadecyloxycarbonyl)phenyl]azo-5-hydroxy-3-methyl-1-phen ylpyrazole 16; and 1-[4-(hexadecyloxycarbonyl) phenyl]-3-methyl-2-pyrazolin-5-one 19. The second class comprises the synthesis of the cyclohexyl ester derivatives; namely 3-substituted-2-(cyclohexyloxycarbonylpropionylthio)-4(3H)-quinazo linones 11a, b, 4-substituted-3-(4-pyridyl)-5-(cyclohexyloxycarbonylpropionylthio) -4 H-1,2,4-triazoles 12a, b and 5-isopropylthio-2-(cyclohexyloxycarbonylpropionylamino)-1,3, 4-thiadiazole 13. The antihypercholesterolemic as well as antihyperlipidemic activities of representative compounds have been studied. All the compounds tested resulted in a decrease in the lipid indices (cholesterol, LDL-cholesterol, HDL-cholesterol and serum triglycerides levels) studied in mice. Compounds 4b, 11a and 12a showed the highest antihyperlipidemic activity; their activities were almost equal to that of beta-sitosterol which was used as a standard.     

Synthesis of some new biologically active thiadiazolotriazinones--part III

4-Amino-6-arylmethyl/tert-butyl-3-mercapto-1,2,4-triazin-5(4H)-ones (1) were condensed with arylfuroic acids (2) to yield 7-(5-aryl-2-furyl)-3-arylmethyl/tert-butyl-4H-1,3,4-thiadiazolo[2,3-c]-1,2,4-triazin-4-ones (3). The newly synthesized compounds exhibited antibacterial activity comparable to that of nitrofurazone. In addition, two compounds displayed in vitro antitumor activity with moderate growth inhibition against a panel of 60 tumor cell lines.     

Novel 3,3a,4,5,6,7-hexahydroindazole and arylthiazolylpyrazoline derivatives as anti-inflammatory agents

A novel series of 7-benzylidene-3, 3a, 4, 5, 6, 7-hexahydro-3-phenyl-2H-indazole substituted at the 2-position were synthesized. The reaction of 2, 6-bis-benzylidenecyclohexanone (1) with thiosemicarbazide in the presence of NaOH afforded a mixture of the 3-H, 3a-H trans 2 and cis 2a diastereoisomers which have been separated by fractional recrystallization. Interaction of the first intermediate 2 with substituted phenacyl bromides, aromatic aldehydes and chloroacetic acid in presence of a mixture of acetic acid and acetic anhydride, and 2, 3-dichloroquinoxaline yielded the corresponding 7-benzylidene-3, 3a, 4, 5, 6, 7-hexahydro-3-phenyl-2H-indazole derivatives substituted at the 2-position with 4-aryl-2-thiazolyl 3a, b, 5-arylidene-4, 5-dihydro-4-oxo-2-thiazolyl 4a, b and thiazolo[4, 5-b]quinoxalin-2-yl 5, respectively. Moreover, the other intermediates 3, 5-diaryl-1-thiocarbamoyl-2-pyrazolines 7a-d were reacted with the previously-mentioned reagents and gave the corresponding 3, 5-diaryl-1-(4-aryl-2-thiazolyl)-2-pyrazolines 8a-h, 3, 5-diaryl-1-(5-arylidene-4, 5-dihydro-4-oxo-2-thiazolyl)-2-pyrazolines 9a-d and 3, 5-diaryl-1-(thiazolo[4, 5-b]quinoxalin-2-yl)-2-pyrazoline derivatives 10a, b, respectively. Some of the newly prepared compounds were subjected to evaluation for their anti-inflammatory activity. The structures of the new compounds were confirmed by elemental analyses as well as (1)H-NMR, IR, and MS data.     

Synthesis and antimicrobial activity of some 1-(2,4-dinitrophenyl)-3-(3-nitrophenyl)-5-(4-substituted phenyl)-4-bromo-2-pyrazolines and 1-(2,4-dinitrophenyl)-3-(3-nitrophenyl)-5-(4-substituted phenyl)-2-pyrazolin-4-ones

A series of 1-(2,4-dinitrophenyl)-3-(3-nitrophenyl)-5-(4-substituted phenyl)-2-pyrazolin-4-ones (4a-e) have been synthesized by the oxidation of 1-(2,4-dinitrophenyl)-3-(3-nitrophenyl)-5-(4-substituted phenyl)-4-bromo-2-pyrazolines (3a-e) with dimethylsulfoxide. The structure has been established on the basis of spectral data (IR,1H NMR). The synthesized compounds have been screened in vitro for their possible antimicrobial activity.     

Cytotoxic phenolic constituents ofAcer tegmentosum maxim

The chromatographic separation of the MeOH extract from the twigs of Acer tegmentosum led to the isolation of ten phenolic compounds. The structures of these compounds were determined using spectroscopic methods as 3,7,3',4'-tetramethyl-quercetin (1), 5,3'-dihydroxy-3,7,4'-trimethoxy flavone (2), 2,6-dimethoxy-p-hydroquinone (3), (-)-catechin (4), morin-3-O-alpha-L-lyxoside (5), p-hydroxy phenylethyl-O-beta-D-glucopyranoside (6), 3,5-dimethoxy-4-hydroxy phenyl-1-O-beta-D-glucoside (7), fraxin (8), 3,5-dimethoxy-benzyl alcohol 4-O-beta-D-glucopyranoside (9) and 4-(2,3-dihydroxy propyl)-2,6-dimethoxy phenyl beta-D-glucopyranoside (10). The compounds were examined for their cytotoxic activity against five cancer cell lines. Compound 3 exhibited good cytotoxic activity against five human cancer cell lines with ED50 values ranging from 1.32 to 3.85 microM.     

Synthesis of new 1,3-oxazolyl-7-chloroquinazolin-4(3H)ones and evaluation of their antimicrobial activities

2-[2-(2,6-Dichlorophenyl)amino]phenylmethyl-3-{4-[(substituted phenyl)amino]-1,3-oxazol-2-yl)-7-chloroquinazolin-4(3H)ones 5a-o have been prepared from 2-[(2,6-dichloro phenyl)amino]phenyl acetic acid 1, which was converted to acid chloride 2 and cyclized with anthranilic acid afforded benzoxazin-4(H)ones 3. Further reaction with urea gave carboxamide-7-chloroquinazolin-4(3H)ones 4 cyclized with substituted phenyl acetamide a-o. All the compounds have been confirmed by elemental analysis, IR, NMR spectral data and evaluated for antimicrobial activity. Compounds 5o, 5k, and 5m (R = 1-H, 2,5-(Cl), and 2-Cl, 4-NO2) showed good activity, compared with the standard drugs.