Synthesis and Antioxidant Evaluation of Some Novel Thiophene,Pyrazole, Chromene,Pyrazolotriazine Derivatives Bearing Sulfonamide Moiety

As a part of ongoing studies in developing new potent antioxidant agents, N‐[4‐(aminosulfonyl)phenyl]‐2‐cyanoacetamide ( 3 ) was utilized as key intermediate for the synthesis of some new thiophene, chromene, and pyrazolotriazine pyridine derivatives. The structures of the newly synthesized compounds were confirmed by elemental analysis, IR, ¹H‐NMR, and mass spectral data. Representative compounds of the synthesized products were tested and evaluated as antioxidant. Compounds 7 and 30 are promising compounds.     

Synthesis and Pharmacological Evaluation of Some New Chromeno[3,4‐c]pyrrole‐3,4‐dione‐based N‐Heterocycles as Antimicrobial Agents

The reaction of 2‐oxo‐2H‐chromene‐3‐carboxamide ( 1 ) with carbon disulfide afforded 1‐mercaptopyrrolo[3,4‐c ]chromene‐3,4‐dione ( 3 ). The latter compound was utilized as versatile building block for new azole systems via incorporating in a series of manipulations including cyclocondensation reactions. The structure of the newly synthesized compounds has been confirmed by IR, ¹H NMR, ¹³C NMR, mass spectral, and elemental analysis. Furthermore, some selected compounds were screened in vitro for their antimicrobial activities. The results declared that most of the synthesized compounds have high antimicrobial activity.     

Synthesis and antioxidant activity of new hydroxy derivatives of chalcones

New hydroxy derivatives of chalcones obtained via a condensation of 3-acetyl-2H-chromen-2-one with 2,4-dihydroxy- and 4-hydroxy-benzaldehydes and via an aldol crotonic condensation of methyl N-(4-acetylphenyl)carbamate with 4-hydroxy-3,5-di(tert-butyl)benzaldehyde have been isolated and characterized. A wide range of promising biological activity of the synthesized compounds, including the radical scavenging and antioxidant ones, was predicted by the in silico method. The anti- and pro-oxidant activities in model systems of peroxidation of cis-9-octadecenoic (oleic) acid and lipids from the liver homogenate of tilapia were estimated in vitro. The presence of sterically hindered hydroxy groups and a chromene moiety provides the prolonged antioxidant activity of new hydroxy derivatives of chalcones.

     

Design,synthesis, characterization,computational study and in-vitro antioxidant and anti-inflammatory activities of few novel 6-aryl substituted pyrimidine azo dyes

A series of 6-aryl substituted pyrimidine azodyes were synthesized by coupling of phenyl pyrimidine 2-amine with different aromatic amines. The synthetic compounds were screened for their in-vitro antioxidant and anti-inflammatory activities. The characterization of the synthesized compounds was carried out by IR, ¹H NMR, ¹³C NMR and Mass spectrophotometry. Computational study of designed compounds was done by OCHEM, Molinspiration cheminformatics, Datawarrior, and Swiss ADME. DPPH assay was used to determine the antioxidant activity and heat hemolysis method for anti-inflammatory activity.     

4‐Aryl‐4H‐Chromene‐3‐Carbonitrile Derivates: Synthesis and Preliminary Anti‐Breast Cancer Studies

A series of new 4‐aryl‐4H‐chromene‐3‐carbonitrile derivatives were obtained by one‐pot synthesis using substituted benzaldehydes, malononitrile, and substituted phenols. All the synthesized compounds ( 1a , 1b , 1c , 1d , 1e ) were screened in vitro for antioxidant and anticancer activities. Compounds 1c , 1d , 1e showed significant antioxidant activity in nitric oxide free radical scavenging method while compounds 1c and 1e showed significant activity in hydrogen peroxide free radical scavenging method. The other compounds showed significant to moderate activities in both the methods in comparison with ascorbic acid and butylated hydroxytoluene as standards. Compounds 1c , 1d , 1e exhibited good anticancer activity, using Michigan Cancer Foundation‐7 (MCF‐7) cell line, compared with those of other synthesized compounds.     

Preparation,structure elucidation,and antioxidant activity of new bis(thiosemicarbazone) derivatives

Schiff-base–bearing new bis(thiosemicarbazone) derivatives were prepared from terephthalaldehyde and various thiosemicarbazides. FT–IR, ¹H NMR, ¹³C NMR, and UV–Vis spectroscopic methods and elemental analysis were used to elucidate the identification of the synthesized molecules. The in vitro antioxidant activity of the synthesized compounds was analysed with the 1,1-diphenyl-2-picryl hydrazyl free-radical–trapping process. The synthesized compounds exhibited lower antioxidant activity than the standard ascorbic acid. IC₅₀ values of the synthesized molecules measured from 3.81 ± 0.01 to 29.05 ± 0.11 μM. Among the synthesized compounds, compound 3 had the best antioxidant activity. Moreover, this study explained the structure–activity relationship of the synthesized molecules with different substituents in radical trapping reactions.     

Synthesis,characterization and evaluation of novel benzothiazole clubbed chromene derivatives for their anti-inflammatory potential

Abstract

A series of chromene derivatives (5a–f) were prepared by multistep synthesis process using 2-[3-phenyl prop-2-ene nitrile] 1,3-benzothiazole and dimedone using piperidine as catalyst in ethanol. The reaction was found to proceed via Knoevenagel condensation of aldehydes with benzothiazole, followed by the elimination to afford the 2-(benzo[d]thiazol-2-yl)-3-(aryl)acrylonitrile, which then undergoes Michael addition with 5,5-dimethyl-1,3-cyclohexanedione, followed by intramolecular O-cyclization to give the products. The structures of all novel constructed derivatives were corroborated by elemental analysis and spectral data (FT-IR, ¹H-NMR, ¹³C-NMR and Mass). Subsequently, the compounds were tested for their in-vivo anti-inflammatory activity. This study revealed that these synthesized derivatives tend to have significantly anti inflammatory activity and shall prove as structural templates in the design and development of new anti inflammatory drugs.     

Reaction of 2-imino-2H-chromene-3-carboxamide with some phosphorus esters: Synthesis of some novel chromenes containing phosphorus heterocycles and phosphonate groups and their antioxidant and cytotoxicity properties

Abstract

Novel chromenyl α-aminophosphonic acid 4 and dialkyl chromenyl phosphonate 6 have been obtained. In addition, some novel types of chromene fused with phosphorus heterocycles such as chromeno[4,3-c][1,2]azaphospholes 5 and 7, chromeno[2,3-d][1,3,2]diazaphosphinine 8 and 1,2-oxaphosphinino[3,4-c]pyridine 10 have been synthesized. The methodology depended on treatment of 2-imino-2H-chromene-3-carboxamide (1) with some phosphorus esters. The synthesized compounds were evaluated for antioxidant and cytotoxic activities. Among the synthesized compounds, compound 5 exhibited the most antioxidant activity with IC₅₀ = 2.8?μg/mL in comparison with ascorbic acid as standard antioxidant. Also, compound 5 had significant cytotoxic effects against four cancer cell lines. Its IC₅₀ values ranged between 4.96 and 7.44?μg/mL in comparison to doxorubicin (IC₅₀ = 0.426–0.493?μg/mL).     

Synthesis and antioxidant screening of new 2-cyano-3-(1,3-diphenyl-1H-pyrazol-4-yl)acryloyl amide derivatives and some pyrazole-based heterocycles

Abstract

The high functionality compound namely 2-cyano-3-(1,3-diphenyl-1H-pyrazol-4-yl)acryloyl chloride (1) was utilized as a building block synthon via reactions with some nitrogen and sulfur nucleophilic reagents. The present work was planned to study the effect of 2-cyano group on the reactivity and stability of C₂–C₃ double bond toward different strong-to-weak nucleophiles, in addition to its facility of nucleophilic addition at C₂–C₃ double bond to construct new heterocyclic derivatives. The proclivity toward some mono-, 1,2-, 1,3-, 1,4-, and 1,5-binucleophiles was investigated. The reaction with 2-cyanoacetohydrazide was mainly dependent on the reaction conditions. Some new heterocycles integrated with pyrazole scaffold were successfully synthesized, such as benzoxazinone, indoline, isoindoline, pyrazolone, chromene, and pyrimidopyrimidine derivatives. Some of the newly synthesized compounds were screened for their antioxidant activity using ABTS method, and the results revealed that some compounds exhibited promising inhibitory antioxidant activity.     

Formation of diaryl sulfides and sulfoxides: Synthesis,characterization and structure activity correlation studies

Abstract

The synthesis of a series of stable diarylsulfides and sulfoxides is reported. All the newly synthesized compounds were characterized by ¹H, ¹³C NMR and mass spectroscopic techniques. A detailed mechanistic study indicates that the formation of sulfoxides follows the oxidation. In addition to synthesis, characterization and mechanistic studies, the glutathione peroxidase(GPx) mimetic activity of the newly synthesized compounds is described. It is observed that the diaryl sulfides having a heterocyclic ring attached to the nitrogen atom facilitates the oxidation of the sulfur center to form the corresponding sulfoxides. The substituents attached to the nitrogen atom play an important role in the catalytic activity of the substituted diaryl sulfides. The obtained data supports for the higher antioxidant activity of diaryl sulfides than that of the corresponding sulfoxides.     

Three-component,one-pot synthesis of pyrano[3,2-c]chromene derivatives catalyzed by ammonium acetate: Synthesis,characterization, cation binding,and biological determination

Three-component reaction of arylaldehydes with malononitrile and 4-hydroxycoumarine using CH₃COONH₄ as a catalyst at reflux was used for the synthesis of novel substituted pyrano[3,2-c]chromene derivatives. The structure of these compounds was assigned by spectroscopic data such as (IR, ¹HNMR, ¹³CNMR, and mass spectral data). The cation binding properties of chromene derivatives 4a-c towards Cu²⁺, Ni²⁺, and Zn²⁺ were studied in methanol. The results showed that Zn²⁺ is the most complexed in this series of cations, and 4c is best complexed with either Ni²⁺ and Zn²⁺. Antimicrobial properties of new pyrano[3,2-c]chromene derivatives are investigated, the compound 4c presents against Micrococcus luteus LB 14110 an MIC value of 0.0185 mg/mL quite better to that of ampicillin (0.0195 mg/mL) used as standard. Concerning acetylcholinesterase inhibition activity (AChEI), compound 4c presents an interesting AChEI activity with an inhibition of 52%.     

Structural studies of 2,5-disubstituted 1,3,4-thiadiazole derivatives from dithioesters under the mild condition: Studies on antioxidant,antimicrobial activities,and molecular docking

Abstract

A series of 2,5-disubstituted 1,3,4-thiadiazole was synthesized and evaluated for their antioxidant and molecular docking studies. These molecules were efficiently synthesized under mild and inexpensive starting material. Construction of these molecules developed using substituted aldehydes and substituted dithioesters in presence of NCS (N-Chorosuccinimide). The compounds 4a, 4b, 4c, 4f, and 4k showed good antibacterial and antioxidant activity among which, 4k possess excellent antibacterial and antioxidant activity. The results of antioxidant activity studies revealed that compound 4k manifested profound antioxidant potential. The molecular docking study was performed with respective newly synthesized compounds to ascertain the binding mode of 4k with respect to the critical proteins involved in biosynthesis and metabolic pathways.     

Synthesis,characterization, DNA binding,antibacterial, and antioxidant activity of new bis-phthalimides

New bis-phthalimides were synthesized by 2: 1 condensation of phthalic anhydride and tetrachlorophthalic anhydride with 1,2,4-triazole-3,5-diamine, pyridine-2,6-diamine, and 4-hydroxypyrimidine- 2,6-diamine. The synthesized compounds were characterized by elemental analyses and IR, ¹H NMR, and mass spectra. Their interaction with calf thymus DNA (ct-DNA) was studied by UV-Vis spectrophotometry, cyclic voltammetry, and viscosity measurements, which revealed intercalative mode of binding to ct-DNA. Antibacterial activity of the synthesized compounds against Escherichia coli and Streptococcus mutans was assessed in vitro by the agar well diffusion method. The antioxidant activity of these compounds was estimated by DPPH assay.     

Synthesis,antimicrobial, and antioxidant activities of new pyridyl‐ and thiazolyl‐bearing carbohydrazides

A series of novel substituted (E)‐N′‐benzylidene‐4‐methyl‐2‐(2‐propylpyridin‐4‐yl)thiazole‐5‐carbohydrazide derivatives ( 6a‐l ) have been synthesized by following the multistep synthetic route starting from prothionamide. The resulting compounds were characterized via ¹H, ¹³C NMR, and HRMS spectral data. The synthesized carbohydrazides were evaluated for their in vitro antimicrobial and antioxidant activities. Tested molecules have displayed moderate to good growth inhibition activity. Among the screened compounds, 6b , 6e , 6j, and 6k are found to be the more promising antimicrobial agents. A 2,2‐diphenyl‐1‐picrylhydrazyl assay was used to test the antioxidant activity of the carbohydrazides. The carbohydrazide derivatives 6b and 6i have shown better free‐radical scavenging ability than the other investigated compounds.     

Synthesis,spectroscopic studies,and antioxidant activities of novel thio/carbohydrazones and bis-isatin derivatives from terephthalaldehyde

New bis(isatins-thio/carbohydrazones) based on Schiff bases were prepared from terephthalaldehyde biscarbohydrazone and 5-substituted isatins in the presence of a drop of sulfuric acid under reflux in ethanol. Terephthalaldehyde bis(thio/carbohydrazone) was synthesized by the reaction of (thio)/carbohydrazide and terephthalaldehyde in the presence of a few drops of acetic acid under reflux in ethanol. The structures of these synthesized compounds were determined using IR, ¹H NMR, and ¹³C NMR spectroscopy and elemental analysis. The in vitro antioxidant activity of all the compounds was determined by the 1,1-diphenyl-2-picryl hydrazyl (DPPH.) free radical scavenging method. Compound 2 showed the best antioxidant activity.     

Synthesis,antimicrobial and antioxidant activity of bis sulfonamide/carbamate derivatives of bis-(4-aminophenyl) methane

A series of new bis sulfonamide/carbamate derivatives of bis-(4-aminophenyl)methane 3 ( a–d )/ 5 ( a–f ) were synthesized from bis-(4-aminophenyl)methane ( 1 ) using various pharmacologically active sulfonyl chlorides 2 ( a–d ) and carbonochloridates 4 ( a–f ) in high yields. The structures of all the newly synthesized compounds were characterized by the Infrared spectroscopy, NMR (¹H and ¹³C), mass, and elemental analyses. Further, all the synthesized compounds were tested for the antioxidant activity by using 2, 2-diphenyl-1-picrylhydrazyl, NO, and H₂O₂ scavenging methods and antimicrobial activity. Most of the compounds exhibited good antioxidant and antimicrobial activities.     

Synthesis and in vitro antioxidant evaluation of new bis(α-aminoalkyl)phosphinic acid derivatives

Diamines were added to arylaldehydes in ethanol, which resulted in corresponding diimines. Novel bis-1-aminophosphinic acid compounds were synthesized through the interaction of diimines and hypophosphorous acid. The new compounds were characterized by elemental analyses, FT-IR and ¹H, ¹³C and ³¹P NMR techniques. The in vitro antioxidant activity of the newly synthesized compounds were measured and found to exhibit significantly higher antioxidant activity than the standard.     

Synthesis,Molecular Docking and Potential Antioxidant Activity of Di/Trisubstituted Pyridazinone Derivatives

A number of pyridazinone derivatives bearing substituted benzylidene and heterocyclic/aromatic rings at 4^th and 6^th positions, respectively were synthesized in good to moderate yields and screened for antioxidant activity. Antioxidant activity of pyridazinone derivatives was evaluated by using several in vitro radical scavenging methods such as 1,1‐diphenylpicrylhydrazyl (DPPH), hydrogen peroxide (H₂O₂), nitric oxide (NO), reducing power, and metal chelating assay etc. Molegro virtual docker software was used to study the binding affinity of the title compounds with the xanthine oxidoreductase enzyme. Amongst the tested compounds, 5a, 5d, 5g & 5j were found to exhibit excellent antioxidant activity at par with the positive control, ascorbic acid. The molecular docking studies of these compounds demonstrated a good selectivity profile with xanthine oxidoreductase receptors. A preliminary study of the structural‐activity relationship showed that the presence of electron withdrawing group and heterocyclic ring on pyridazinone nucleus are associated with the best potency and selectivity profile. It could be proposed that xanthine oxidoreductase receptor may be involved in observed antioxidant activity of pyridazinone derivatives bearing aromatic ring and benzylidene substituents and thus the synthesized compounds are worthy of further exploration.     

Facile Synthesis of 3,6‐Disubstituted‐1,2,4‐triazolo‐[3,4‐b]‐1,3,4‐thiadiazoles via Oxidative Cyclization of n‐Heteroaryl‐Substituted Hydrazones and Their Biological Activity

Fused 3,6‐disubstituted triazolothiadiazoles were synthesized in good yield from a rapid and convenient oxidative cyclization of N‐heteroaryl‐substituted hydrazones promoted by chloramine‐T trihydrate at ambient temperature. The structure of the synthesized compounds was confirmed by FTIR, ¹H NMR, ¹³C NMR, and mass spectral data. The synthesized compounds were evaluated for their antioxidant and antitubercular activities. All the compounds 5a‐i and 6a‐i showed good antitubercular activity. However, only compounds 5a‐i showed good antioxidant activity.     

Synthesis,characterization, and antioxidant activity of heterocyclic Schiff bases

Schiff base derivatives have gained great importance due to revealing a great number of biological properties. Schiff bases were synthesized by treatment of 4-amino-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one ( 1 ) with various aldehydes in methanol at reflux. In addition, diamine was reacted with an aldehyde to yield the corresponding Schiff bases. The structures of synthesized Schiff bases were elucidated by spectroscopic methods such as microanalysis, ¹H-NMR, ¹³C-NMR, and FTIR. Antioxidant activities of synthesized Schiff bases were carried out using different antioxidant assays such as 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH^•) scavenging, 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging, and reducing power activity. (E)-4-((1H-indol-3-yl)methyleneamino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one ( 3 ), (E)-1,5-dimethyl-4-((2-methyl-1H-indol-3-yl)methyleneamino)-2-phenyl-1H-pyrazol-3(2H)-one ( 5 ), (E)-1,5-dimethyl-2-phenyl-4-(thiophen-2-ylmethyleneamino)-1H-pyrazol-3(2H)-one ( 7 ), (E)-1,5-dimethyl-2-phenyl-4-(quinolin-2-ylmethyleneamino)-1H-pyrazol-3(2H)-one ( 9 ), (1S,2S,N1,N2)-N1,N2-bis((1H-indol-3-yl)methylene)cyclohexane-1,2-diamine ( 11 ), and (1S,2S,N1,N2)-N1,N2-bis((2-methyl-1H-indol-3-yl)methylene)cyclohexane-1,2-diamine ( 12 ) were synthesized in high yields. Compound 5 displayed a good ABTS^•+ activity. Compound 3 revealed the outstanding activity in all assays. Compound 7 has the best-reducing power ability in comparison to other synthesized compounds. Although compounds 5, 11, 12 are new, compounds 3, 7, 9 are known. Due to revealing a good antioxidant activity, the synthesized compounds ( 3, 5, 7 ) have the potential to be used as synthetic antioxidant agents.