New approach to the synthesis of substituted 7H‐furo[3,2‐b]pyran‐7‐ones based on 5‐hydroxy‐2‐methyl‐4H‐pyran‐4‐one derivatives

A convenient approach to the synthesis of the previously unknown 7H‐furo[3,2‐b]pyran‐7‐ones based on the intramolecular cyclization of carbonyl derivatives of 5‐hydroxy‐2‐methyl‐4H‐pyran‐4‐one has been elaborated. Key intermediates in the synthesis of the target 7H‐furo[3,2‐b]pyran‐7‐ones are 3‐hydroxy‐6‐methyl‐2‐(2‐oxo‐2‐arylethyl)‐4H‐pyran‐4‐ones. They are formed as a result of multicomponent condensation of 5‐hydroxy‐2‐methyl‐4H‐pyran‐4‐one with arylglyoxals and 4‐methoxyaniline.     

4‐hydroxy‐6‐methyl‐3‐(5‐phenyl‐2E,4E‐pentadien‐1‐oyl)‐2H‐pyran‐2‐one: Synthesis and reactivity with amines

The synthesis and reactivity studies of 4‐hydroxy‐6‐methyl‐3‐(5‐phenyl‐2E,4E‐pentadien‐1‐oyl)‐2H‐pyran‐2‐one 2 with nucleophiles are reported. Reactions of 2 with hydrazine derivatives gave new pyrazole‐type com pounds while the reaction with ortho‐phenylenediamines yielded 1,5‐benzodiazepines. The reaction of 2 with ethylamine implies the 2H‐pyran‐2‐one ring opening and the formation of a strong conjugated compound 3.     

A Simple Synthesis of 2‐{(Arylmethylidene)hydrazinylidene]‐3‐hydroxy‐4H‐furo[3,2‐c]pyran‐4(3H)‐ones

A simple synthesis of 2‐hydrazinylidene‐3‐hydroxy‐4H‐furo[3,2‐c]pyran‐4‐ones is described. A mixture of (isocyanoimino)(triphenyl)phosphorane, an aromatic aldehyde, and dehydroacetic acid (=3‐acetyl‐2‐hydroxy‐6‐methyl‐4H‐pyran‐4‐one) undergo a 1 : 1 : 1 addition reaction under mild conditions to afford the title compounds in excellent yields.     

Synthesis and reactivity of 6‐methyl‐4H‐furo[3,2c]pyran‐3,4‐dione

An efficient synthesis of 3‐bromoacetyl‐4‐hydroxy‐6‐methyl‐2H‐pyran‐2‐one by bromination of dehydroacetic acid in glacial acetic acid is described. Novel 4‐hydroxy‐6‐methyl‐3‐(2‐substituted‐thiazol‐4‐yl)‐2H‐pyran‐2‐ones have been prepared from the reaction of 3‐bromoacetyl‐4‐hydroxy‐6‐methyl‐2H‐pyran‐2‐one with thioamides, thiourea, and diphenylthiocarbazone. The condensation reaction of 6‐methyl‐4H‐furo[3,2c]pyran‐3,4‐dione, obtained from the reaction of 3‐bromoacetyl‐4‐hydroxy‐6‐methyl‐2H‐pyran‐2‐one with aliphatic amines, with benzaldehydes and acetophenones led to novel 2‐arylidene‐6‐methyl‐2H‐furo[3,2‐c]pyran‐3,4‐diones and 6‐(2‐arylprop‐1‐enyl)‐2H‐furo[3,2‐c]pyran‐3,4‐diones. The structure of all compounds was established by elemental analysis, IR, NMR, and mass spectra. J. Heterocyclic Chem., 2011.     

New synthesis and reactivity of 3‐bromoacetyl‐4‐hydroxy‐6‐methyl‐2H‐pyran‐2‐one with binucleophilic amines

3‐(Bromoacetyl)‐4‐hydroxy‐6‐methyl‐2H‐pyran‐2‐one was synthesized by the reaction of dehydroacetic acid (DHAA) with bromine in glacial acetic acid. Novel heterocyclic products were synthesized from the reaction of bromo‐DHAA with alkanediamines, phenylhydrazines, ortho‐phenylenediamines, and ortho‐aminobenzenethiol. The obtained new products 3‐(2‐N‐substituted‐acetyl)‐4‐hydroxy‐6‐methyl‐2H‐pyran‐2‐ones, 4‐hydroxy‐3‐[1‐hydroxy‐2‐(2‐phenylhydrazinyl)vinyl]‐6‐methyl‐2H‐pyran‐2‐one, 1‐(2,4‐dinitrophenyl)‐7‐methyl‐2,3‐dihydro‐1H‐pyrano[4,3‐c]pyridazine‐4,5‐dione, 3‐(3,4‐dihydroquinoxalin‐2‐yl)‐4‐hydroxy‐6‐methyl‐2H‐pyran‐2‐one/3‐(3,4‐dihydroquinoxalin‐2‐yl)‐6‐methyl‐2H‐pyran‐2,4(3H)‐dione, 6‐methyl‐3‐(3,4‐dihydroquinoxalin‐2‐yl)‐2H‐pyran‐2,4(3H)‐dione, and (E)‐3‐(2H‐benzo[b][1,4]thiazin‐3(4H)‐ylidene)‐6‐methyl‐2H‐pyran‐2,4(3H)‐dione were fully characterized by IR, ¹H and ¹³C NMR, and mass spectra. J. Heterocyclic Chem., 2011.     

Synthesis of 3‐thiocyanato‐1H,3H‐quinoline‐2,4‐diones

4‐Hydroxy‐1H‐quinolin‐2‐ones ( 1 ) react with thiocyanogen in acetic acid to the corresponding 3‐thiocyanato‐1H,3H‐quinoline‐2,4‐diones ( 2 ) in good yields. In some cases, 3‐bromo‐1H,3H‐quinoline‐2,4‐diones ( 4 ) were isolated as minor reaction products. Compounds 2 are very reactive towards nucleophiles and easily hydrolyze to the corresponding 4‐hydroxy‐1H‐quinoline‐2‐ones ( 1 ).     

Ring Opening of 2‐(Benzylamino)‐2H‐1,4‐benzoxazin‐3(4H)‐ones and 2‐Bromo‐2H‐1,4‐benzoxazin‐3(4H)‐ones

Substituted 2‐(benzylamino)‐2H‐1,4‐benzoxazin‐3(4H)‐ones are unstable under alkaline and acidic conditions, undergoing opening of the benzoxazinone ring. 2‐Bromo‐2H‐1,4‐benzoxazin‐3(4H)‐ones show similar degradation under alkaline conditions, while replacement of Br at C(2) to give 2‐hydroxy‐2H‐1,4‐benzoxazin‐3(4H)‐ones was observed only under mild alkaline conditions. Mechanisms of ring opening and degradation to 2‐aminophenol derivatives are proposed.     

Synthesis of 10‐Aryl‐10H‐naphtho[1,8a,8‐fg]indazol‐7‐ones

3‐Hydroxy‐2‐[1‐(arylhydrazono)ethyl]‐1H‐phenalen‐1‐ones 3 , obtained from 2‐acetyl‐3‐hydroxy‐1H‐phenalen‐1‐one ( 1 ) and arylhydrazines 2 , cyclize under acidic conditions to 8‐methyl‐10‐aryl‐10H‐naphtho‐[1,8a,8‐fg]indazol‐7‐ones 4 . Indazoles 4 are also obtained from 2‐acetyl‐3‐hydroxy‐1H‐phenalen‐1‐one ( 1 ) and arylhydrazines 2 in a one‐pot reaction. 2‐Acetyl‐3‐azido‐1H‐phenalen‐1‐one ( 6 ) does not give 8‐methyl‐9‐arylamino‐9H‐naphtho[1,8a,8‐fg]indazol‐7‐ones via azide decomposition but gives again by nucleophilic replacement of the azide moiety in 6 the indazole 4 .     

An Efficient Synthesis of N‐Substituted‐3‐aryl‐3‐(4‐hydroxy‐6‐methyl‐2‐oxo‐2H‐pyran‐3‐yl)propanamides by Four‐Component Reaction in Aqueous Medium

A mild and efficient synthesis of N‐substituted‐3‐aryl‐3‐(4‐hydroxy‐6‐methyl‐2‐oxo‐2H‐pyran‐3‐yl)propanamides via four‐component reaction of an aldehyde, amine, Meldrum's acid, and 4‐hydroxy‐6‐methyl‐2H‐pyran‐2‐one in the presence of benzyltriethylammonium chloride (TEBAC) in aqueous medium is described. This method has the advantages of accessible starting materials, good yields, mild reaction conditions, and begin environmentally friendly.     

Synthesis and reactions of 11H‐benzo[b]pyrano[3,2‐f]indolizines an pyrrolo[3,2,1‐ij]pyrano[3,2‐c]quinolines

2‐Methyl‐3H‐indoles 1 cyclize with two equivalents of ethyl malonate 2 to form 4‐hydroxy‐11H‐benzo[b]pyrano[3,2‐f]indolizin‐2,5‐diones 3, whereas 2‐mefhyl‐2,3‐dihydro‐1H‐indoles 9 give under similar conditions regioisomer 8‐hydroxy‐5‐methyl‐4,5‐dihydro‐pyrrolo[3,2,1‐ij]pyrano[3,2‐c]quinolin‐7,10‐diones 10 . The pyrone rings of 3 and 9 can be cleaved either by alkaline hydrolysis to give 7‐acetyl‐8‐hydroxy‐10H‐pyrido[1,2‐a]indol‐6‐ones 4 or 5‐acetyl‐6‐hydroxy‐2‐methyl‐1,2‐dihydro‐4H‐pyrrolo‐[3,2,1‐ij]quinolin‐4‐ones 11 , respectively. Chlorination of 3 and 9 with sulfurylchloride gives under subsequent ring opening 7‐dichloroacetyl‐8‐hydroxy‐10H‐pyrido[1,2‐a]indol‐6‐ones 5 or 5‐dichloracetyl‐6‐hydroxy‐2‐methyl‐1,2‐dihydro‐4H‐pyrrolo[3,2,1‐ij]quinolin‐4‐ones 12 . The dichloroacetyl group of 5 can be reduced with zinc to 7‐acetyl‐8‐hydroxy‐10H‐pyrido[1,2‐a]indol‐6‐ones 7. Treatment of the acetyl compounds 4, 7 and 11 with 90% sulfuric acid cleaves the acetyl group and yields 8‐hydroxy‐10H‐pyrido[1,2‐a]‐indol‐6‐ones 6 and 8 , and 6‐hydroxy‐2‐methyl‐1,2‐dihydro‐4H‐pyrrolo[3,2,1‐ij]quinolin‐4‐ones 13 . Reaction of dichloroacetyl compounds 12 with sodium azide yields 6‐hydroxy‐2‐methyl‐5‐(1H‐tetrazol‐5‐ylcarbonyl)‐1,2‐dihydro‐4H‐pyrrolo[3,2,1‐ij]quinolin‐4‐ones 14 via intermediate geminal diazides.     

An easy route to 2‐substituted‐2,3‐dihydro‐5(7)H‐oxazolo[3,2‐a]pyrimidin‐5‐ones and 7‐ones starting from the corresponding 2‐amino‐2‐oxazolines

The isomeric 2‐substituted‐7(5)‐methyl‐2,3‐dihydro‐5(7)H‐oxazolo[3,2‐a]pyrimidin‐5‐ones 3a‐b and 7‐ones 2a‐b,7a were synthesized by cyclocondensation from the 5‐substituted‐2‐amino‐2‐oxazolines 1a‐b with biselectrophiles. In boiling ethanol, the reaction of 1a‐b with acetylenic esters led to a mixture of 2a‐b,7a with a small amount of (E)‐2‐N‐(2‐ethoxycarbonylethylene)‐5‐substituted‐2‐iminooxazolines 5a‐b . The ring annulation between 1a‐b and diketene gave the 2‐substituted‐7‐hydroxy‐7‐methyl‐2,3,6,7‐tetrahydro‐5H‐oxazolo[3,2‐ a ]pyrimidin‐5‐ones 4a‐b which can be easily dehydrated to provide the 2‐substituted‐7‐methyl‐2,3‐dihydro‐5H‐oxazolo[3,2‐a]pyrimidin‐5‐ones 3a‐b .     

Synthesis anti‐fungal and anti‐bacterial screening of 3‐phenyl‐1,4,5‐trihydro‐pyrazol and 2, 4‐dihydro[ 1,2,4]‐triazol‐3‐one derivatives of 4‐hydroxy‐2‐oxo‐2H‐1‐benzopyran

4‐Hydroxy‐2‐oxo‐2H‐1‐benzopyran‐3‐carboxaldehydes 2a‐d are prepared from 4‐hydroxy‐2‐oxo‐2H‐1‐benzopyrans 1a‐d via the Vielsmeyer Haack reaction. The 4‐hydroxy‐2‐oxo‐3‐(3′oxo‐3′‐phenylprop‐1′‐enyl)‐2H‐1‐benzopyrans 3a‐d are obtained from 2a‐d via the Claisen reaction. Refluxing compounds 3a‐d with hydrazine hydrate gave the 3‐phenyl‐5‐(4‐hydroxy‐2‐oxo‐2H‐1‐benzopyran‐3‐yl)‐1,4,5‐trihydropyra‐zols 4a‐d . Stirring compounds 2a‐d with semicarbazide hydrochloride in acidic medium gave the 4‐hydroxy‐2‐oxo‐2H‐1‐benzopyran‐3‐aldehyde‐semicarbazone 5a‐d , which on cyclisation with ferric chloride hexahydrate gave the 5‐(4‐hydroxy‐2‐oxo‐2H‐1‐benzopyran‐3‐yl)‐2,4‐dihydro[1,2,4]triazol‐3‐ones 6a‐d . All these compounds show significant antibacterial activities.     

Synthesis of 3‐Acetyl‐4‐hydroxy‐1‐phenylpyridin‐2(1H)‐one Derivatives

The cyclization of aryl ketone anilides 3 with diethyl malonate to affords 4‐hydroxy‐6‐phenyl‐6H‐pyrano[3,2‐c]‐pyridin‐2,5‐diones 4 in good yields. 3‐Acetyl‐4‐hydroxy‐1‐phenylpyridin‐2(1H)‐ones 5 are obtained by ring‐opening reaction of 4‐hydroxy‐6‐phenyl‐6H‐pyrano[3,2‐c]‐pyridin‐2,5‐diones 4 in the presence of 1,2‐diethylene glycol. The reaction of 3‐acetyl‐4‐hydroxy‐1‐phenylpyridin‐2(1H)‐ones 5 with hydroxylamine hydrochloride produces 4‐hydroxy‐3‐[N‐hydroxyethanimidoyl]‐1‐phenylpyridin‐2(1H)‐ones 6 from which 3‐alkyloxyiminoacetyl‐4‐hydroxy‐1‐phenylpyridin‐2(1H)‐ones 7 are obtained by reacting with alkyl bromides or iodides in the presence of anhydrous potassium carbonate with moderate yields. The similar compounds can be synthesized on refluxing 3‐acetyl‐4‐hydroxy‐1‐phenylpyridin‐2(1H)‐ones 5 with substituted hydroxylamine hydrochloride in the presence of sodium bicarbonate with good yields. Most of the synthesized compounds are characterized by IR and NMR spectroscopic methods.     

An Efficient Synthesis of 3‐(3‐benzyl‐2‐(phenylimino)‐2,3‐dihydrothiazol‐4‐yl)‐6‐methyl‐4‐(2‐oxo‐2‐phenylethoxy)‐3,4‐dihydro‐2H‐pyran‐2‐one Derivatives via Multi‐Component Approach

An easy, highly efficient and a new convenient one‐pot, two‐step approach to the synthesis of 3‐(3‐benzyl‐2‐(phenylimino)‐2,3‐dihydrothiazol‐4‐yl)‐6‐methyl‐4‐(2‐oxo‐2‐phenylethoxy)‐3,4‐dihydro‐2H‐pyran‐2‐one is described. These compounds were synthesized from 3‐(3‐benzyl‐2‐(phenylimino)‐2,3‐dihydrothiazol‐4‐yl)‐4‐hydroxy‐6‐methyl‐3,4‐dihydro‐2H‐pyran‐2‐one and α‐bromoketones in good yields. The compounds 4 were synthesized by a multi‐component reaction between 1 , 2 , and 3 and the prominent features of this protocol are mild reaction conditions, operation simplicity, and good to high yields of products.     

Synthesis and reactions of 3‐amino‐2‐methyl‐3H‐[1,2,4]triazolo[5,1‐b]‐quinazolin‐9‐one and 2‐hydrazino‐3‐phenylamino‐3H‐quinazolin‐4‐one

The reaction of 3‐N‐(2‐mercapto‐4‐oxo‐4H‐quinazolin‐3‐yl)acetamide ( 1 ) with hydrazine hydrate yielded 3‐amino‐2‐methyl‐3H‐[1,2,4]triazolo[5,1‐b]quinazolin‐9‐one ( 2 ). The reaction of 2 with o‐chlorobenzaldehyde and 2‐hydroxy‐naphthaldehyde gave the corresponding 3‐arylidene amino derivatives 3 and 4 , respectively. Condensation of 2 with 1‐nitroso‐2‐naphthol afforded the corresponding 3‐(2‐hydroxy‐naphthalen‐1‐yl‐diazenyl)‐2‐methyl‐3H‐[1,2,4]triazolo[5,1‐b]quinazolin‐9‐one ( 5 ), which on subsequent reduction by SnCl₂ and HCl gave the hydrazino derivative 6. Reaction of 2 with phenyl isothiocyanate in refluxing ethanol yielded thiourea derivative 7. Ring closure of 7 subsequently cyclized on refluxing with phencyl bromide, oxalyl dichloride and chloroacetic acid afforded the corresponding thiazolidine derivatives 8, 9 and 10 , respectively. Reaction of 2‐mercapto‐3‐phenylamino‐3H‐quinazolin‐4‐one ( 11 ) with hydrazine hydrate afforded 2‐hydrazino‐3‐phenylamino‐3H‐quinazolin‐4‐one ( 12 ). The reactivity 12 towards carbon disulphide, acetyl acetone and ethyl acetoacetate gave 13, 14 and 15 , respectively. Condensation of 12 with isatin afforded 2‐[N‐(2‐oxo‐1,2‐dihydroindol‐3‐ylidene)hydrazino]‐3‐phenylamino‐3H‐quinazolin‐4‐one ( 16 ). 2‐(4‐Oxo‐3‐phenylamino‐3,4‐dihydroquinazolin‐2‐ylamino)isoindole‐1,3‐dione ( 17 ) was synthesized by the reaction of 12 with phthalic anhydride. All isolated products were confirmed by their ir, ¹H nmr, ¹³C nmr and mass spectra.     

3/4‐phenylene bisheterocycles from ring transformation reaction of sydnone derivatives: Synthesis of 3‐[3/4‐heterocyclyl]phenyl‐5‐methyl‐3H‐[1,3,4]‐oxadiazol‐2‐ones from 3/4‐acetylphenylsydnones and their biological properties

The bifunctional 3/4‐[acetyl]phenylsydnones 1a, 1b were subjected to a one‐pot ring conversion to 3‐[3/4‐acetyl]phenyl‐5‐methyl‐3H‐[1,3,4]‐oxadiazol‐2‐ones 2a, 2b , which on further bromination yielded the 3‐[3/4‐bromoacyl]phenyl‐5‐methyl‐3H‐[1,3,4]‐oxadiazol‐2‐ones 3a, 3b . Reaction of these compounds with thiourea yielded the 3‐[3/4‐(2‐aminothiazol‐4‐yl)]phenyl‐5‐methyl‐3H‐[1,3,4]‐oxadiazol‐2‐ones 4a, 4b . The other thiazole derivatives 5a, 5b–7a, 7b were prepared by using thiosemicarbazide, thioacetamide, and thiobenzamide, respectively. In another reaction of the bromoacetyl compounds ( 3a, 3b ) with 2‐aminopyridine and 2‐aminothiazole, the fused biheterocyclic compounds 3‐[3/4‐imidazo‐[1,2‐a]pyridine‐2‐yl]phenyl‐5‐methyl‐3H‐[1,3,4]‐oxadiazol‐2‐ones 8a, 8b and 3‐[3/4‐imidazo‐[2,1‐b]‐thiazol‐6‐yl]phenyl‐5‐methyl‐3H‐[1,3,4]‐oxadiazol‐2‐ones 9a, 9b were obtained. The 3‐[3/4‐(benzofuran‐2‐carbonyl)]phenyl‐5‐methyl‐3H‐[1,3,4]‐oxadiazol‐2‐ones 10a, 10b were obtained by treatment of compounds 3a, 3b with o‐hydroxy benzaldehyde. Most of these compounds exhibited antifungal activity greater than the reference drugs used. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:50–54, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20255     

Synthesis and Characterization of Novel 1‐Methyl‐3‐(4‐phenyl‐4H‐1,2,4‐triazol‐3‐yl)‐1H‐indazole Derivatives

A series of novel 1‐methyl‐3‐(4‐phenyl‐4H‐1,2,4‐triazol‐3‐yl)‐1H‐indazoles was synthesized in three steps from 5‐(1‐methyl‐1H‐indazol‐3‐yl)‐4‐phenyl‐2H‐1,2,4‐triazole‐3(4H)‐thiones. 5‐(1‐Methyl‐1H‐indazol‐3‐yl)‐4‐phenyl‐2H‐1,2,4‐triazole‐3(4H)‐thiones were converted into 1‐methyl‐3‐(5‐(methylsulfonyl)‐4‐phenyl‐4H‐1,2,4‐triazol‐3‐yl)‐1H‐indazoles upon methylation followed by treatment with aq. KMnO₄. The reaction of 1‐methyl‐3‐(5‐(methylsulfonyl)‐4‐phenyl‐4H‐1,2,4‐triazol‐3‐yl)‐1H‐indazoles with Raney nickel resulted in desulphonylation to afford corresponding 1‐methyl‐3‐(4‐phenyl‐4H‐1,2,4‐triazol‐3‐yl)‐1H‐indazoles. All the new synthesized compounds were characterized by spectral techniques.     

1‐Methyl‐3‐phenyl‐3‐thiocyanato‐1H,3H‐quinoline‐2,4‐dione: A novel thiocyanating agent

Under mild reaction conditions, the thiocyanato group is selectively transferred from 1‐methyl‐3‐phenyl‐3‐thiocyanato‐1H,3H‐quinoline‐2,4‐dione ( 3 ) to some nucleophiles. Aliphatic primary and secondary amines are converted to S‐cyanothiohydroxylamines, anilines afford p‐thiocyanatoanilines, Wittig reagent is thiocyanated in α‐position, and thiols are oxidized to disulfides.     

A simple synthesis of 4‐chloro‐5‐hydroxy‐1H‐benzo[g]indoles

The reaction of methyl 2‐(3‐chloro‐1,4‐dioxo‐1,4‐dihydronaphthalen‐2‐yl)propenoate ( 2a ) with primary amines gave 4‐chloro‐5‐hydroxy‐3‐methoxycarbonyl‐1H‐benzo[g]indoles 5a‐f as major compounds and 3‐methoxycarbonyl‐4,9‐dioxo‐2,3,4,9‐tetrahydro‐1H‐benzo[f]indoles 6a‐d as minor ones. Whereas the reaction of 3‐(3‐chloro‐1,4‐dioxo‐1,4‐dihydronaphthalen‐2‐yl)‐3‐buten‐2‐one ( 2b ) with primary amines afforded the corresponding 1H‐benzo[g]indoles 5g‐i as major products and 3‐acetyl‐4,9‐dihydro‐4,9‐dioxo‐1H‐benzo[f]indoles 7g, h as minor products.     

Green approach for the synthesis of 3‐methyl‐1‐phenyl‐4‐((2‐phenyl‐1H‐indol 3‐yl)methylene)‐1H‐pyrazole‐5(4H)‐ones and their DNA Cleavage,antioxidant, and antimicrobial activities

3‐Methyl‐1‐phenyl‐4‐((2‐phenyl‐1H‐indol‐3‐yl)methylene)‐1H‐pyrazol‐5(4H)‐ones (5a‐i) was prepared by the condensation reaction of different 3‐formyl‐2‐phenylindole derivatives (2a‐i) and 3‐methyl‐1‐phenyl‐2‐pyrazoline‐5‐one in quantitative yield by applying various green synthetic methods as grinding, microwave irradiation using different catalysts under solvent‐free mild reaction conditions with high product yields. The structures of the synthesized compounds were characterized on the basis of elemental analysis, infrared, ¹HNMR, ¹³C NMR, and mass spectral data. The synthesized compounds were screened for free radical scavenging, antimicrobial, and DNA cleavage activities. Most of the tested compounds belonging to the 3‐methyl‐1‐phenyl‐4‐((2‐phenyl‐1H‐indol‐3‐yl)methylene)‐1H‐pyrazol‐5(4H)‐ones series exhibited promising activities.