Synthesis of Some 3‐(4‐Aryl‐benzofuro[3,2‐b]pyridin‐2‐yl)coumarins and Their Antimicrobial Screening

The synthesis of some 3‐(4‐aryl‐benzofuro[3,2‐b]pyridin‐2‐yl)coumarins 3a–r has been carried out by the reaction of 3‐coumarinoyl methyl pyridinium salts 1a–c with 2‐arylidene aurones 2a–f in the presence of ammonium acetate and acetic acid under Kröhnke's reaction conditions. All the synthesized compounds were characterized by analytical and spectral data. They have been screened for their antibacterial activity against Escherichia coli (ATCC 25922) as Gram‐negative bacteria, Bacillus subtillis (ATCC 1633) as Gram‐positive bacteria and antifungal activity against Aspergillus niger (ATCC 9029).     

Synthesis and Antimicrobial Screening of Some Novel 2‐(5‐(4‐(1H‐Benzo[d][1,2,3]triazol‐1‐yl)phenyl)‐4,5‐dihydro‐1H‐pyrazol‐3‐yl)phenols Incorporated by Triazole Moiety

A novel series of 2‐(5‐(4‐(1H‐benzo[d][1,2,3]triazol‐1‐yl)phenyl)‐4,5‐dihydro‐1H‐pyrazol‐3‐yl)phenols derivative has been synthesized from (E)‐3‐(4‐(1H‐benzo[d][1,2,3]triazol‐1‐yl)phenyl)‐1‐(2‐hydroxyphenyl)prop‐2‐en‐1‐ones in ethanol and hydrazine hydrate under reflux condition. The synthesized compounds were screened for antibacterial activity against Gram‐positive bacteria viz Staphylococcus aureus and Bacillus subtilis and Gram‐negative bacteria viz Escherichia coli and Salmonella typhi, respectively. Some of the tested compounds showed significant antimicrobial activity. IR, ¹H NMR, mass spectral data, and elemental analysis elucidated the structures of all the newly synthesized compounds.     

Synthesis and antimicrobial activity of novel 2‐(aryl)‐3‐[5‐(2‐oxo‐2H‐3‐chromenyl)‐1,3‐oxazol‐2‐yl]‐1,3‐thiazolan‐4‐ones

A series of novel 2‐(aryl)‐3‐[5‐(2‐oxo‐2H‐3‐chromenyl)‐1,3‐oxazol‐2‐yl]‐1,3‐thiazolan‐4‐ones 4a , 4b , 4c , 4e , 4f , 4g , 4h , 4i , 4j have been synthesized and assayed for their antibacterial activity against Gram‐positive bacteria viz. Bacillus subtilis (ATCC 6633), Staphylococcus aureus (ATCC 6538p), Micrococcus luteus (IFC 12708), and Gram‐negative bacteria viz. Proteus vulgaris (ATCC 3851), Salmonella typhimurium (ATCC 14028), Escherichia coli (ATCC 25922), and also antifungal activity against Candida albicans (ATCC 10231), Aspergillus fumigatus (HIC 6094), Trichophyton rubrum (IFO 9185), and Trichophyton mentagrophytes (IFO 40996). Among the screened compounds, 4d , 4e , 4f , 4g , and 4j exhibited potent inhibitory activity compared with the standard drug at the tested concentrations. The results reveal that, the presence of difluorophenyl in 4f and pipernyl ring in 4j at 2‐position of thiazolidine‐4‐one ring show significant inhibitory activity. The other compounds also showed appreciable activity against the test bacteria and fungi and emerged as potential molecules for further development. J. Heterocyclic Chem., 2011.     

Facile Synthesis of N‐(Benzyl‐1H‐1,2,3‐Triazol‐5‐yl) Methyl)‐4‐(6‐Methoxybenzo [d] Thiazol‐2‐yl)‐2‐Nitrobenzamides via Click Chemistry

A series of novel N‐((l‐benzyl‐lH‐l,2,3‐triazol‐5‐yl) methyl)‐4‐(6‐methoxy benzo[d ]thiazol‐2‐yl)‐2‐nitrobenzamide derivatives were prepared from 4‐(6‐methoxybenzo[d ]thiazol‐2‐yl)‐2‐nitro‐N‐(prop‐2‐ynyl) benzamide with benzyl azides by using click reaction (copper‐catalyzed Huisgen 1,3‐dipolar cycloaddition reaction) in the presence of CuSO₄.5H₂O and sodium ascaorbate. All the newly synthesized compounds were evaluated further in vitro antimicrobial activity against Gram‐positive bacteria (Staphylococcus aureus and Bacillus subtillis ), Gram‐negative bacteria (Echerichia coli and Pseudomonas aeuroginosa ), and fungi (Aspergillus niger and Aspergillusfumigatus ) strains. The new compounds were characterized based on spectroscopic evidence. Among them compounds 10a , 10h , and 10i were showed promising activity when compared with standard drugs Ciprofloxacin and Miconazole.     

Synthesis and biological evaluation of new 4‐(4‐(1‐benzyl‐1H‐1,2,3‐triazol‐4‐yl)phenyl)‐2‐phenylthiazole derivatives

A novel series of 4‐(4‐(1‐benzyl‐1H‐1,2,3‐triazol‐4‐yl)phenyl)‐2‐substitutedthiazole derivatives ( 8a‐l) have been synthesized by [3 + 2] cycloaddition reaction of 4‐(4‐ethynylphenyl)‐2‐substitutedthiazole with substituted benzyl azide in aqueous DMF. Starting compounds 4‐(4‐ethynylphenyl)‐2‐substitutedthiazole ( 6a‐d ) were synthesized by reaction of 4‐(2‐substitutedthiazol‐4‐yl)benzaldehyde with Ohira‐Bestmann reagent in methanol. The structures of these novel triazole‐thiazole clubbed derivatives were confirmed by the spectral analysis. The title compounds ( 8a‐l ) were tested for antimycobacterial activity against Mycobacterium tuberculosis H37Ra active and dormant (MTB, ATCC 25177) and antimicrobial activity against standard Gram‐positive bacteria, Staphylococcus aureus (NCIM 2602) and Bacillus subtilis (NCIM 2162), and Gram‐negative bacteria, Escherichia coli (NCIM 2576) and Pseudomonas flurescence (NCIM 2059). Compounds 8a , 8b , 8c , and 8h reported good activity against B subtilis, compounds 8a , 8b , and 8c showed good activity against S aureus, and compound 8b showed good activity against dormant M tuberculosis H37Rv strain. Compounds 8b and 8c found more potent against Gram positive and dormant M tuberculosis H37Rv strains. These novel triazole‐thiazole clubbed analogues found to be a capable leads for further optimization and development.     

Preparation and Reactions of 2‐Methyl‐7‐(3‐methyl‐5‐oxo‐1‐phenyl‐2‐pyrazolin‐4‐yl)‐5‐arylthiazolo[3,2‐a]‐pyrimido[4,5‐d]oxazin‐4(5H)‐one

Ethyl 7‐amino‐3‐(3‐methyl‐5‐oxo‐1‐phenyl‐2‐pyrazolin‐4‐yl)‐5‐aryl‐5H‐thiazolo[3,2‐a]pyrimidine‐6‐carboxylate was hydrolyzed with an ethanolic sodium hydroxide and the sodium salt thus formed underwent cyclization with acetic anhydride to afford 2‐methyl‐7‐(3‐methyl‐5‐oxo‐1‐phenyl‐2‐pyrazolin‐4‐yl)‐5‐arylthiazolo[3,2‐a]pyrimido[4,5‐d]oxazin‐4(5H)‐one. This compound was transformed to related heterocyclic systems via its reaction with various reagents. The biological activity of the prepared compounds was tested against Gram positive and Gram negative bacteria as well as yeast‐like and filamentous fungi. They revealed in some cases excellent biocidal properties.     

Microwave‐assisted Synthesis of Hybrid Heterocyclics as Biological Potent Molecules

A series of novel 5‐((1H‐benzo[d]imidazol‐2‐yl)methyl)‐2‐((3aR,5S,6S,6aR)‐2,2‐dimethyl‐6‐((1‐phenyl‐1H‐1,2,3‐triazol‐4‐yl)methoxy)tetrahydrofuro[2,3‐d][1,3]dioxol‐5‐yl)‐3‐phenylthiazolidin‐4‐ones 9a–n has been synthesized from triazole‐linked thiazolidinone derivatives 8a–g with o‐phenylenediamine and characterized by IR, NMR, MS, and elemental analyses. Further, these compounds were screened for their antibacterial activity against Gram‐positive bacteria, namely, Bacillus subtilis (ATCC 6633), Staphylococcus aureus (ATCC 6538p), and Micrococcus luteus (IFC 12708), and Gram‐negative bacteria, namely, Proteus vulgaris (ATCC 3851), Salmonella typhimurium (ATCC 14028), and Escherichia coli (ATCC 25922). Among the screened compounds, compounds 9b , 9d , 9h , and 9i are highly active against almost all selected bacterial strains; the remaining compounds showed moderate to good activity and emerged as potential molecules for further development.     

Synthesis and Antifungal Screening of 2‐(2‐Aryl‐4‐methyl‐thiazol‐5‐yl)‐5‐((2‐aryl/benzylthiazol‐4‐yl)methyl)‐1,3,4‐oxadiazole Derivatives

A new series of synthesis and biological screening of 2‐(2‐aryl‐4‐methyl‐thiazol‐5‐yl)‐5‐((2‐aryl/benzylthiazol‐4‐yl)methyl)‐1,3,4‐oxadiazole derivatives 5a , 5b , 5c , 5d , 5e , 5f , 5g , 5h , 5i was achieved by condensation of 2‐(2‐aryl/benzylthiazol‐4‐yl)acetohydrazide 2a , 2b , 2c with 4‐methyl‐2‐arylthiazole‐5‐carbaldehyde 3a , 3b , 3c followed by oxidative cyclization of N'‐((4‐methyl‐2‐arylthiazol‐5‐yl)methylene)‐2‐(2‐aryl/benzylthiazol‐4‐yl)acetohydrazide 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i using iodobenzene diacetate as oxidizing agent. All the synthesized compounds were screened for their in vitro antifungal activity against Candida albicans, Candida tropicalis, Aspergillus niger, and Aspergillus flavus. Some of the synthesized compounds showed good antifungal activity.     

Synthesis and antibacterial evaluation of some new 4‐substituted‐3‐aryl‐1‐(2,6‐dimethylpyrimidin‐4‐yl)pyrazoles

Synthesis of a series of new 4‐substituted‐3‐aryl‐1‐(2,6‐dimethylpyrimidin‐4‐yl)pyrazoles ( 2a , 2b , 2c , 2d , 2e , 2f , 2g , 3a , 3b , 3c , 3d , 3e , 3f , 3g , and 4a , 4b , 4c , 4d , 4e , 4f , 4g ) is described. All the synthesized compounds were evaluated in vitro for their antibacterial activity against two gram‐positive and two gram‐negative bacteria, namely, Bacillus subtilis (MTCC 8509), Bacillus stearothermophilus (MTCC 8508), Escherichia coli (MTCC 51), and Pseudomonas putida (MTCC 121), and their activity was compared with two commercial antibiotics, streptomycin and chloramphenicol. Two compounds, namely, 3‐(4‐anisyl)‐1‐(2,6‐dimethylpyrimidin‐4‐yl)pyrazole‐4‐carboxaldehyde ( 2b ) and 3‐(2‐thienyl)‐1‐(2,6‐dimethyl pyrimidin‐4‐yl)pyrazole‐4‐carboxaldehyde ( 2g ) were found to be equipotent to streptomycin and chloramphenicol against gram‐negative bacteria, E. coli having minimum inhibitory concentration (MIC) value = 4 μg/mL. Compounds 4b and 4d also displayed good activity against E. coli with MIC = 8 μg/mL. J. Heterocyclic Chem., (2011).     

Synthesis and Antimicrobial Screening of 2‐Aryl‐5‐((2‐arylthiazol‐4‐yl)methyl)‐1,3,4‐oxadiazole Derivatives

A new series of 2‐aryl‐5‐((2‐arylthiazol‐4‐yl)methyl)‐1,3,4‐oxadiazole derivatives was synthesized by condensation of 2‐(2‐substituted thiazol‐4‐yl)acetohydrazide with aryl aldehydes followed by oxidative cyclocondensation using iodobenzene diacetate. The structure of synthesized compounds was characterized by IR, NMR, and mass analysis. All the newly synthesized compounds were evaluated for their in vitro antimicrobial activity. Some of the compounds showed moderate antimicrobial activity.     

Synthesis and Antimicrobial Activity of N‐[(2Z)‐3‐(4,6‐Substitutedpyrimidin‐2‐yl)‐4‐phenyl‐1,3‐thiazol‐2(3H)‐ylidene]‐3, 5‐dinitrobenzamide Analogues

In this study, we have synthesized 1‐(4,6‐disubstitutedpyrimidin‐2‐yl)‐3‐(3,5‐dinitrobenzoyl)‐thiourea derivatives ( 1a , 1b , 1c , 1d , 1e , 1f , 1g , 1h ) and N‐[(2Z)‐3‐(4,6‐disubstitutedpyrimidin‐2‐yl)‐4‐phenyl‐1,3‐thiazol‐2(3H)‐ylidene]‐3, 5‐dinitrobenzamide ( 2a‐2h ) analogues and characterized by IR spectroscopy, NMR spectroscopy, elemental analysis, and single crystal X‐ray diffraction data. The compounds ( 2a‐2h ) were screened for antimicrobial activity against Gram positive, Gram negative, and fungal species. The results of antimicrobial study indicated that compounds showed most potential and appreciable antibacterial and antifungal activities.     

Conformational study of (Z)‐5‐(4‐chlorobenzylidene)‐2‐[4‐(2‐hydroxyethyl)piperazin‐1‐yl]‐3H‐imidazol‐4(5H)‐one in different environments: insight into the structural properties of bacterial efflux pump inhibitors

The 2‐amine derivatives of 5‐arylidene‐3H‐imidazol‐4(5H )‐one are a new class of bacterial efflux pump inhibitors, the chemical compounds that are able to restore antibiotic efficacy against multidrug resistant bacteria. 5‐Arylidene‐3H‐imidazol‐4(5H )‐ones with a piperazine ring at position 2 reverse the mechanisms of multidrug resistance (MDR) of the particularly dangerous Gram‐negative bacteria E. coli by inhibition of the efflux pump AcrA/AcrB/TolC (a main multidrug resistance mechanism in Gram‐negative bacteria, consisting of a membrane fusion protein, AcrA, a Resistant‐Nodulation‐Division protein, AcrB, and an outer membrane factor, TolC). In order to study the influence of the environment on the conformation of (Z )‐5‐(4‐chlorobenzylidene)‐2‐[4‐(2‐hydroxyethyl)piperazin‐1‐yl]‐3H‐imidazol‐4(5H )‐one, ( 3 ), two different salts were prepared, namely with picolinic acid {systematic name: 4‐[(Z )‐4‐(4‐chlorobenzylidene)‐5‐oxo‐3,4‐dihydro‐1H‐imidazol‐2‐yl]‐1‐(2‐hydroxyethyl)piperazin‐1‐ium pyridine‐2‐carboxylate, C₁₆H₂₀ClN₄O₂⁺·C₆H₄NO₂⁻, ( 3 a )} and 4‐nitrophenylacetic acid {systematic name: 4‐[(Z )‐4‐(4‐chlorobenzylidene)‐5‐oxo‐3,4‐dihydro‐1H‐imidazol‐2‐yl]‐1‐(2‐hydroxyethyl)piperazin‐1‐ium 2‐(4‐nitrophenyl)acetate, C₁₆H₂₀ClN₄O₂⁺·C₈H₆NO₄⁻, ( 3 b )}. The crystal structures of the new salts were determined by X‐ray diffraction. In both crystal structures, the molecule of ( 3 ) is protonated at an N atom of the piperazine ring by proton transfer from the corresponding acid. The carboxylate group of picolinate engages in hydrogen bonds with three molecules of the cation of ( 3 ), whereas the carboxylate group of 4‐nitrophenylacetate engages in hydrogen bonds with only two molecules of ( 3 ). As a consequence of these interactions, different orientations of the hydroxyethyl group of ( 3 ) are observed. The crystal structures are additionally stabilized by both C—H…N [in ( 3 a )] and C—H…O [in ( 3 a ) and ( 3 b )] intermolecular interactions. The geometry of the imidazolone fragment was compared with other crystal structures possessing this moiety. The tautomer observed in the crystal structures presented here, namely 3H‐imidazol‐4(5H )‐one [systematic name: 1H‐imidazol‐5(4H )‐one], is also that most frequently observed in other structures containing this heterocycle.     

An efficient synthesis of 5‐aryl‐4,5‐dihydro‐3‐(5‐methyl‐1‐p‐tolyl‐1H‐1,2,3‐triazol‐4‐yl)‐1‐(4‐phenylthiazol‐2‐yl)pyrazoles

Some new target products 5‐aryl‐4,5‐dihydro‐3‐(5‐methyl‐1‐p‐tolyl‐1H‐1,2,3‐triazol‐4‐yl)‐1‐(4‐phenylthiazol‐2‐yl)pyrazoles 5a , 5b , 5c , 5d , 5e , 5f , 5g , 5h , 5i , 5j have been synthesized by reaction of 2‐bromo‐1‐phenylethanone and compounds 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i , 4j which were prepared from the combination of thiosemicarbazide and (E)‐3‐aryl‐1‐(5‐methyl‐1‐p‐tolyl‐1H‐1,2,3‐triazol‐4‐yl)‐prop‐2‐en‐1‐ones 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h , 3i , 3j . All the structures were established by MS, IR, CHN, and ¹H NMR spectra data. Synthesis of structure diversity is applied. J. Heterocyclic Chem., (2011).     

A “One Pot,” Environmentally Friendly,Multicomponent Synthesis of 2‐Amino‐5‐cyano‐4‐[(2‐aryl)‐1H‐indol‐3‐yl]‐6‐hydroxypyrimidines and Their Antimicrobial Activity

A series of multifunctional 2‐amino‐5‐cyano‐4‐[(2‐aryl)‐1H‐indol‐3‐yl]‐6‐hydroxypyrimidines ( 4a , 4b , 4c , 4d , 4e , 4f ) was synthesized by multicomponent reaction of 3‐formylindole ( 1 ), cyanoethylacetate ( 2 ), and guanidine hydrochloride ( 3 ) with NaOH by using green chemical techniques, viz. microwave irradiation and grindstone technology. The same reactants when refluxed in ethanol also gave titled compounds ( 4a , 4b , 4c , 4d , 4e , 4f ). Compared with conventional procedure, the reaction can be carried out under milder conditions, requiring a shorter reaction time and giving higher yields following the green chemistry methodology. All the synthesized compounds have been characterized on the basis of elemental analyses and spectral data (IR, ¹H NMR, ¹³C NMR, and mass). All synthesized compounds were also evaluated for their antimicrobial activity against nine pathogenic bacteria, antifungal activity against Rhizopus stolonifer, Aspergillus flavus, and Fusarium oxysporum and antibacterial activity against Escherichia coli and Pseudomonas aeruginosa at different concentrations. Most of the compounds showed mild to moderate activity.     

Design and Synthesis of Novel 6‐(5‐Methyl‐1H‐1,2,3‐triazol‐4‐yl)‐5‐[(2‐(thiazol‐2‐yl)hydrazono)methyl]imidazo[2,1‐b]thiazoles as Antimicrobial Agents

Novel 6‐(1,2,3‐triazol‐4‐yl)‐5‐[(2‐(thiazol‐2‐yl)hydrazono)methyl]imidazo[2,1‐b ]thiazoles 7 , 9a , 9b , 9c , 9d , and 11 were prepared by reaction of thiosemicarbazone 5a , 5b with either hydrazonoyl chloride 6 , phenacylbromides 8 or 2‐bromo‐1‐(5‐methyl‐1‐p‐tolyl‐1H‐1,2,3‐triazol‐4‐yl)ethanone 10 respectively. The new products were tested for their antimicrobial activities using 96‐well micro‐plate assay, and compound 7 showed excellent antibacterial activities compared with Vancomycine (reference drugs), while compounds 5b and 9c exhibited good results against yeast. The minimum inhibitory concentration (MIC) was determined, and compound 7 showed the lowest MIC against Gram positive bacteria while compound 5b showed the lowest MIC against yeast.     

Synthesis and Antifungal Activities of ω‐[4‐Aryl‐5‐(1‐phenyl‐5‐methyl‐1,2,3‐triazol‐4‐yl)‐1,2,4‐triazol‐3‐thio]‐ω‐(1H‐1,2,4‐triazol‐1‐yl)acetophenones

New 4‐aryl‐5‐(1‐phenyl‐5‐methyl‐1,2,3‐triazol‐4‐yl)‐1,2,4‐triazol‐3‐thiones 3 have been synthesized by the intramolecular cyclization of 4‐aryl‐1‐(1‐phenyl‐5‐methyl‐1,2,4‐triazol‐4‐formyl)thiosemicarbazides 2 with an 8% NaOH solution, and then 3 reacted with ω‐bromo‐ω‐(1H‐1,2,4‐triazol‐1‐yl)acetophenone to afford ω‐[4‐aryl‐5‐(1‐phenyl‐5‐methyl‐1,2,3‐triazol‐4‐yl)‐1,2,4‐triazol‐3‐thio]‐ω‐(1H‐1,2,4‐triazol‐1‐yl)‐acetophenones 4 . The preliminary biological test showed that the representative compounds possess some anti fungal activities.     

Synthesis of 2‐Aryl‐2,3‐dihydro‐1,8‐naphthyridin‐4(1H)‐ones by Deprotective Cyclization of N‐{3‐[(2E)‐3‐Arylprop‐2‐enoyl]pyridin‐2‐yl}‐2,2‐dimethylpropanamides in Water

A new and convenient method for the preparation of 2‐aryl‐2,3‐dihydro‐1,8‐naphthyridin‐4(1H)‐ones 4 has been developed. Thus, N‐{3‐[(2E)‐3‐arylprop‐2‐enoyl]pyridin‐2‐yl}‐2,2‐dimethylpropanamides 3 are synthesized from commercially available pyridin‐2‐amine using an easily performed three‐step sequence and are subjected to cyclization with deprotection under acidic conditions in H₂O to give the desired products. Similarly, 2‐aryl‐2,3‐dihydro‐1,7‐naphthyridin‐4(1H)‐ones 8 and 2‐aryl‐2,3‐dihydro‐1,6‐naphthyridin‐4(1H)‐ones 12 can be prepared from pyridin‐3‐amine and pyridin‐4‐amine, respectively.     

Synthesis of (3,5‐Aryl/methyl‐1H‐Pyrazol‐1‐yl)‐(5‐Arylamino‐2H‐1,2,3‐Triazol‐4‐yl)Methanone

Some new (3,5‐aryl/methyl‐1H‐pyrazol‐1‐yl)‐(5‐arylamino‐2H‐1,2,3‐triazol‐4‐yl)methanones were synthesized and characterized by ¹HNMR, ¹³C NMR, MS, IR spectra data and elemental analyses or high resolution mass spectra (HRMS). During the procedure, Dimroth rearrangement was used in this synthesis.     

Synthesis and Antimicrobial Activity of N‐Aryl‐4‐(cyano/alkoxycarbonyl)‐5‐(pyridin‐3‐yl)‐1H/3H‐1,2,3‐triazole Derivatives

A convenient synthesis of a new series of N‐aryl‐5‐(pyridin‐3‐yl)‐1H/3H‐1,2,3‐triazole‐4‐carbonitriles and alkyl N‐aryl‐5‐(pyridin‐3‐yl)‐1H/3H‐1,2,3‐triazole‐4‐carboxylic acid esters is reported. The newly synthesized 5‐(pyridin‐3‐yl)‐1,2,3‐triazole derivatives are evaluated for their antibacterial and antifungal activity. Some of these triazole derivatives have exhibited moderate antimicrobial activity.     

Synthesis of Some New Heterocycles Derived from Ethyl 7‐Amino‐3‐(3‐methyl‐5‐oxo‐1‐phenyl‐2‐pyrazolin‐4‐yl)‐5‐aryl‐5H‐thiazolo[3,2‐a]pyrimidine‐6‐carboxylate of Biological Importance

Ethyl 7‐amino‐3‐(3‐methyl‐5‐oxo‐1‐phenyl‐2‐pyrazolin‐4‐yl)‐5‐aryl‐5H‐thiazolo[3,2‐a]pyrimidine‐6‐carboxylate was synthesized by the reaction of 4‐(2‐aminothiazol‐4‐yl)‐3‐methyl‐5‐oxo‐1‐phenyl‐2‐pyrazoline with arylidene ethyl cyanoacetate and it transformed to related fused heterocyclic systems via reaction with various reagents. The biological activities of these compounds were evaluated.