Reaction Of Chalcones Research Articles

Synthesis and characterization of novel benzo[d][1,3]dioxole gathered pyrazole derivatives and their antimicrobial evaluation

Benzo[d][1,3]dioxole gathered pyrazole derivatives (4a–i) were synthesized by the reaction of chalcones with phenyl hydrazine in presence of absolute alcohol as a solvent. Chalcones were prepared by the Claisen-Schmidt reaction between 1-(benzo[d][1,3]dioxol-5-yl)ethanone (2) and substituted aromatic aldehydes. The synthesized compounds were characterized by spectral and elemental analysis data. Furthermore, Benzo[d][1,3]dioxole gathered pyrazole derivatives (4a–i) were evaluated for their in vitro antimicrobial activity. Among the newly synthesized compounds 4a, 4c, 4 g and 4 h showed the excellent antifungal activity and as well as 4a and 4d showed the excellent antibacterial activity when compared to other compounds.

SYNTHESIS, CHARACTERIZATION AND ANTIMICROBIAL ACTIVITY OF NOVEL PYRAZOLO[3,4-b]PYRIDINES AND THEIR SPIRO-HETEROCYCLIC DERIVATIVES

The present work describes the synthesis of a novel series of heterocyclic moieties derived from 5-acetylpyrazolo[3,4-b]pyridine (1). The formation of chalcones (2a-d) was utilized to synthesize pyrazoline, isoxazoline and pyrimidine derivatives (3-10). Thiosemicarbazone and semicarbazone (11, 17) were utilized to synthesize other new triazolethiones, thiadiazole and selenadiazole derivatives (11-19). Some new spiro derivatives (22-25) were synthesized by the reaction of chalcone (21) of 1 and isatine with hydrazines, hydroxyl amines and thiourea. Also, The reaction of 1 with cyanoacetyl hydrazine gave the hydrazide-hydrazone derivative 26, which was allowed to react with aromatic aldehydes and α-cyanocinnamonitrile to afford coumarine and substituted pyridine derivatives (28, 29). The structures of all the new compounds have been established on the basis of their analytical and spectral data. Twenty two of the synthesized compounds were also evaluated for their antibacterial and antifungal activity against various strains of bacteria and fungi and most are found to possess promising antimicrobial activity when compared with Chloramphenicol and Clotrimazole

Synthesis and AChE Inhibitory Activity of Chalcones Mannich Base Derivatives

Chalcone flavokawain A (1) and chalcone prenyl ether derivative 2 were synthesized from naringin, through glycoside hydrolysis, O-methylation or O-prenylation, and base-catalyzed ring-opening reaction. Based on Mannich reaction of chalcone 1 and chalcone prenyl ether derivative 2, fourteen new chalcone Mannich base derivatives 3~16 were synthesized. The aminomethylation occurred preferentially at 3'-C position of chalcones. The structures of all synthesized compounds were determined by MS, NMR and IR spectra. All the synthetic compounds were evaluated for acetylcholinesterase (AChE) inhibitory activity. The results show that chalcone mannich base derivatives 3~5, 9 exhibit good AChE inhibitory activity.

Synthesis of 3-(2-(4,5-Dihydro-3,5-diphenylpyrazol-1-yl)thiazol-4-yl)-2H-chromen-2-one Derivatives via Multicomponent Approach

An efficient synthesis of 3-(2-(4,5-dihydro-3,5-diphenylpyrazol-1-yl)thiazol-4-yl)-2H-chromen-2-one derivatives by a simple, atom-economical, and multicomponent reaction of chalcones, thiosemicarbazide, and 3-(2-bromoacetyl) coumarins in the presence of aqueous sodium hydroxide in refluxing ethanol is reported. The structures of newly prepared compounds have been confirmed by their analytical and spectral (IR, 1HNMR, 13CNMR and mass) data. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]

Synthesis of some new heterocyclic compounds derived from 2-Chloro-3-formyl quinoline

In this paper the Synthesis of some substituted 2-Chloro-3-formyl quinoline (2a–d) by treating various substituted acetanilide or 1-(4-substituted phenyl) ethanone oxime with POCl3 in dimethyl formamide. It proceeds through Vilsmeier – Haack cyclization. The condensation of 2-chloro-3-formylquinoline with p-Hydroxyacetophenone, 2-acetyl pyridine, 2-acetyl furan or 3-acetyl indole via Claisene– Schmiatcondensations gives quinolinylchalcone (4a – d). Newpyrazoline derivatives were synthesized by condensing the appropriate chalcone (4a) with hydrazine hydrate or phenylhydrazine (10 – 11). Oxazole (12) is reported from compound (4a) and hydroxyl amine hydrochloride is in basic medium. The reaction of chalcone (4a) with urea, thiourea or quinidine hydrochloride gives pyrimidine-2-one (7), pyrimidine-2-thiol (8) or 2- amino pyrimidine (9) respectively.Oxirane (6) prepared from reaction of chalcone (4a) with hydrogen peroxide in basic medium. The reaction of chalcone (4a) with bromine gives dibromide (5). The structures of synthesized compounds were confirmed by spectral and physical methods.

ChemInform Abstract: Synthesis and Study of Antibacterial and Antifungal Activities of Some New Hydroxychalcone‐Based Azo Dyes.

AbstractNovel hydroxychalcone azo dyes and related bis azo dyes are synthesized by reaction of chalcones with aniline diazonium salts.

ChemInform Abstract: Magnesium Methoxide‐Assisted Synthesis of 2,4,6‐Triaryl Pyridines.

AbstractThe title Kroehnke pyridines are obtained in a novel, facile three‐component reaction of chalcones, ketones, and ammonia.

ChemInform Abstract: PEG Mediated Synthesis and Pharmacological Evaluation of Some Fluoro Substituted Pyrazoline Derivatives and Antiinflammatory and Analgesic Agents.

AbstractNovel fluoro‐substituted pyrazolinylpyrazoline derivatives are synthesized by PEG‐mediated reaction of chalcones (I) with hydrazine derivatives.

Synthesis of polysubstituted pyridines via reactions of chalcones and malononitrile in alcohols using Amberlite IRA-400 (OH−)

Polysubstituted pyridine derivatives were synthesized through economical one-pot multicomponent reactions of different α,β-unsaturated ketones, malononitrile, and ethanol or methanol in the presence of Amberlite IRA-400 (OH−) at room temperature. The catalyst is recyclable several times without substantial loss of activity. Other valuable features include the wide range of functional group tolerance, easy and clean synthesis with a simple work-up procedure, and excellent yields under mild conditions.

ChemInform Abstract: N‐Bromosuccinimide/1,8‐Diazabicyclo[5.4.1]undec‐7‐ene Combination: β‐Amination of Chalcones via a Tandem Bromoamination/Debromination Sequence.

A one-pot cascade transformation of chalcones into β-imidoketones has been developed, in which NBS provides both electrophilic bromine and nucleophilic nitrogen sources, and DBU functions as a nucleophilic reagent to activate NBS to be a more electrophilic bromine species and to further remove the bromine of α-bromoketones. The whole process involves tandem bromoamination and debromination, which represents a unique example of preparing β-aminoketones by the reaction of chalcones with the NBS/DBU combination.

Magnesium Methoxide-Assisted Synthesis of 2,4,6-Triaryl Pyridines

A new three-component reaction of chalcones, ketones, and ammonia assisted by magnesium methoxide is described. The corresponding 2,4,6-triaryl pyridines (Kröhnke pyridines) are formed in fair to good yields (34–76%) within 3 h. The method also provides a facile way to synthesize 2(6)-difluoromethyl pyridines via an interesting mechanism.

N-Bromosuccinimide/1,8-Diazabicyclo[5.4.1]undec-7-ene Combination: β-Amination of Chalcones via a Tandem Bromoamination/Debromination Sequence

A one-pot cascade transformation of chalcones into β-imidoketones has been developed, in which NBS provides both electrophilic bromine and nucleophilic nitrogen sources, and DBU functions as a nucleophilic reagent to activate NBS to be a more electrophilic bromine species and to further remove the bromine of α-bromoketones. The whole process involves tandem bromoamination and debromination, which represents a unique example of preparing β-aminoketones by the reaction of chalcones with the NBS/DBU combination.

Clean and efficient microwave assisted synthesis of some new pyrimidine, pyrazoline and isoxazoline derivatives from 3-(3-nitrophenyl)-N-phenyl-prop-2-enamide

A rapid and efficient method for the preparation of some new pyrimidine , pyrazoline and isoxazoline derivatives by the reaction of chalcones with hydroxylamine, urea and hydrazine hydrate under microwave exposure has been reported. The products have been isolated, purified and characterized by spectral methods like IR, NMR and mass spectrometry. The antibacterial and antifungal activities of the final products against various bacteria and fungi have also been reported.

Synthesis, X-ray crystal structure and optical properties of novel 1,3,5-triarylpyrazoline derivatives and the fluorescent sensor for Cu2+

A series of novel 1,3,5-triarylpyrazoline derivatives was synthesized by the reaction of chalcone and 5-aryl-2-hydrazinyl-1,3,4-thiadiazole in 43.3–84.7% yields. The structures of compounds were characterized using IR, 1H NMR and HRMS spectroscopy and X-ray diffraction analysis. The absorption and fluorescence characteristics of the compounds were investigated in dichloromethane, toluene, acetonitrile, N,N-dimethylformamide and tetrahydrofuran. The results showed that the absorption maxima of the compounds vary from 366 to 370nm depending on the group bound to benzene rings. The maximum emission spectra of the compounds in dichloromethane were dependent on nature of groups in benzene ring. Furthermore, the compound 3b can be used to determine Cu2+ ion with high selectivity and a low detection limit in the DMF:H2O=1:1 (v/v) solution.

ChemInform Abstract: Unusual Michael Reaction of 3‐(4‐Chlorophenyl)‐1‐phenylprop‐2‐en‐1‐one with 3‐Amino‐N‐phenyl‐3‐thioxopropanamide.

AbstractNaOH‐mediated reaction of chalcone (I) with thioxopropanamide (II) in EtOH does not yield the expected pyridinethione (V), but a Michael type adduct (III).

Alternate Synthesis Route of 2-(Substituted Phenyl)-3,3a-dihydro-8H-pyrazolo[5,1-a]isoindol-8-ones via Chalcone-Based N-Formyl-pyrazolines

An alternate approach to 2-(substituted phenyl)-3,3a-dihydro-8H-pyrazolo[5,l-a] isoindol-8-ones via chalcone-based N-formyl-pyrazolines is described. N-Formyl-pyrazolines were prepared in excellent yield (81–96%) by the reaction of chalcones with hydrazine hydrate in the presence of formic acid, which undergoes intramolecular Friedel–Crafts acylation in the presence of trifluoroacetic acid (TFA) as a catalyst to afford functionalized 2-(substituted phenyl)-3,3a-dihydro-8H-pyrazolo[5,1-a]isoindol-8-ones in good to excellent yield (74–94%) at reflux in acetonitrile. Our synthetic route avoids expensive reagents and significantly improves yields.

Unusual michael reaction of 3-(4-Chlorophenyl)-1-phenylprop-2-en-1-one with 3-amino-N-phenyl-3-thioxopropanamide

Chlorophenyl)-1-phenylprop-2-en-1-one reacted with 3-amino-N-phenyl-3-thioxopropanamide under basic conditions in ethanol to give a mixture of 3-(4-chlorophenyl)-2-cyano-5-oxo-N,5-diphenyl- pentanamide and 3-(4-chlorophenyl)-1,5-diphenylpentane-1,5-dione. The structure of the former was deter- mined by X-ray analysis. The reaction of the same compounds in DMSO in the presence of sodium hydroxide produced 4-(4-chlorophenyl)-N,6-diphenyl-2-thioxo-1,2,3,4-tetrahydropyridine-3-carboxamide. We previously reported on the synthesis of N-phenyl-2-thioxo-1,2,3,4-tetrahydropyridine-3-car- boxamides from chalcones and 3-amino-N-phenyl-3- thioxopropanamide (II) (1). In the present communi- cation we describe the reaction of 3-(4-chlorophenyl)- 1-phenylprop-2-en-1-one (I) with compound II. The reaction in ethanol in the presence of sodium hydrox- ide did not produce the expected product, 4-(4-chloro- phenyl)-N,6-diphenyl-2-thioxo-1,2,3,4-tetrahydropyri- dine-3-carboxamide (III) (1), but afforded 3-(4-chloro- phenyl)-2-cyano-5-oxo-N,5-diphenyl-pentanamide (IV) (presumably as a result of elimination of hydro- gen sulfide from hypothetical primary Michael adduct A) and 3-(4-chlorophenyl)-1,5-diphenylpentane-1,5-di- one (V) (Scheme 1). The latter is likely to be formed via exchange of methylene components, which is known for analogous reactions (see also (2)). In the reaction of chalcone I with amide II in DMSO in the presence of sodium hydroxide at room temperature we isolated only expected 4-(4-chloro- phenyl)-N,6-diphenyl-2-thioxo-1,2,3,4-tetrahydropyr- idine-3-carboxamide (III). Addition of methyl iodide to the reaction mixture, other conditions being equal, resulted in the formation of substituted pyridine VI. In the 1 H NMR spectrum of IV all proton signals were doubled. No appreciable change of the spectral pattern was observed on heating to 70°C (DMSO-d6); only the amide proton signal was displaced upfield by 0.3 ppm. These findings indicated free rotation of the amide fragment. The structure of IV was determined by X-ray analysis (see figure). The phenacyl group on C 1 occupies +sc-position

Synthesis, X-ray crystal structure and optical properties research of novel diphenyl sulfone-based bis-pyrazoline derivatives

A series of novel bis-pyrazoline derivatives were synthesized by the reaction of chalcone and (sulfonylbis(3,1-phenylene))bis(hydrazine) in 20–34% yields. The structures of the compounds were determined by IR, 1H NMR, HRMS spectra, and a representative compound 3b was confirmed based on the X-ray crystallographic analysis. Absorption and fluorescence spectra of these compounds in dichloromethane solution were investigated. The results showed that the emission maxima varied from 415 to 444 nm mainly depending on C3 substituents of pyrazoline moiety. The compounds had higher quantum yields, when C3 substituent was an electron-withdrawing p-chlorophenyl group. Moreover, absorption spectra and emission spectra exhibited a blue-shift and a red-shift with increasing the polarity of solvents, respectively. Fluorescent molecules happened to collide with each other and resulted in quench of the fluorescence when the concentration increased over to 10 −5 M.

Synthesis and evaluation of novel 2-butyl-4-chloro-1-methylimidazole embedded chalcones and pyrazoles as angiotensin converting enzyme (ACE) inhibitors

A series of novel 2-butyl-4-chloro-1-methylimidazole embedded aryl and heteroaryl derived chalcones and pyrazoles were synthesized and evaluated for their angiotensin converting enzyme (ACE) inhibitory activity. The condensation of 2-butyl-4-chloro-1-methylimidazole-5-carboxaldehyde with various aryl and heteroaryl methyl ketones in the presence of 10% aqueous NaOH in methanol proceeded efficiently to give the respective chalcones in very good yields. Further, the reaction of chalcones with hydrazine hydrate in acetic acid gave substituted pyrazole analogues. Screening all 36 new compounds using ACE inhibition assay, resulted chalcones with better ACE inhibitory activity compared to the respective pyrazole analogues. Among the chalcones 4a–r, three compounds, (E)-3-(2-butyl-4-chloro-1-methyl-1H-imidazol-5-yl)-1-(5-chlorothiophen-2-yl)prop-2-enone 4i, (E)-3-(2-butyl-4-chloro-1-methyl-1H-imidazol-5-yl)-1-(1H-pyrrol-2-yl)prop-2-enone 4l, (E)-3-(2-butyl-4-chloro-1-methyl-1H-imidazol-5-yl)-1-(dibenzo[b,d] thiophen-2-yl)prop-2-enone 4q were resulted as most active ACE inhibitors with IC50 of 3.60μM, 2.24μM, and 2.68μM, respectively.

Enantioselective Conjugate Addition of Nitro Compounds to α,β‐Unsaturated Ketones: An Experimental and Computational Study

A series of chiral thioureas derived from easily available diamines, prepared from α-amino acids, have been tested as catalysts in the enantioselective Michael additions of nitroalkanes to α,β-unsaturated ketones. The best results are obtained with the bifunctional catalyst prepared from L-valine. This thiourea promotes the reaction with high enantioselectivities and chemical yields for aryl/vinyl ketones, but the enantiomeric ratio for alkyl/vinyl derivatives is very modest. The addition of substituted nitromethanes led to the corresponding adducts with excellent enantioselectivity but very poor diastereoselectivity. Evidence for the isomerization of the addition products has been obtained from the reaction of chalcone with [D(3)]nitromethane, which shows that the final addition products epimerize under the reaction conditions. The epimerization explains the low diastereoselectivity observed in the formation of adducts with two adjacent tertiary stereocenters. Density functional studies of the transition structures corresponding to two alternative activation modes of the nitroalkanes and α,β-unsaturated ketones by the bifunctional organocatalyst have been carried out at the B3LYP/3-21G* level. The computations are consistent with a reaction model involving the Michael addition of the thiourea-activated nitronate to the ketone activated by the protonated amine of the organocatalyst. The enantioselectivities predicted by the computations are consistent with the experimental values obtained for aryl- and alkyl-substituted α,β-unsaturated ketones.