| 95% |
With 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-Heptadecafluorodecylnicotinate In octane at 80℃; for 16h; |
|
| 95% |
With sodium hydroxide In ethanol; water for 4h; Cooling with ice; |
Preparation of the Chalcones
General procedure: An Illustrative Procedure with (E)-1-Aryl-3-(2-pyrrolyl)-2-propenones (3k). 2-Pyrrolecarbaldehyde (12 mmol), acetophenone (13 mmol), and 24 mmol of NaOH in ethanol (20 mL) and water (10 mL) were mixed in an ice-bath and stirred for 4 h in the bath. The mixture was neutralized with 1 M-HCl aqueous solution to pH 8-9. The resulting precipitate was collected and recrystallized from ethanol. |
| 95% |
Stage #1: (4-nitrophenyl)ethanone With sodium hydroxide In methanol at 20℃; for 0.0833333h;
Stage #2: benzaldehyde In methanol at 20℃; for 16h; |
|
| 94% |
With sodium hydroxide In ethanol; water at 20℃; for 4h; |
|
| 93% |
With chloro-trimethyl-silane In N,N-dimethyl-formamide at 75℃; for 5h; |
|
| 92% |
In methanol at 20℃; for 16h; |
|
| 86% |
With sodium hydroxide In water at 20℃; Cooling with ice; |
Synthesis of (E)-chalcones 1a-j
General procedure: Into a 25 mL flask was added ethanol (1 mL), acetophenone (1 mmol) and a solution of NaOH (507 mg) in H2O (450 μL). The reaction mixture was placed in an ice bath, and benzaldehyde was slowly added (102 μL, 1 mmol). The mixture was stirred for 2 to 6 h at room temperature and then neutralized with aqueous solution of NH4Cl (5 mL), extracted with AcOEt (3 x 30 mL). The organic phase was dried over Na2SO4 and then concentrated under vacuum. |
| 86% |
With nitrogen doped BaO/fly ash for 0.0333333h; Microwave irradiation; |
Synthesis of chalcone
General procedure: Microwave irradiation method: An appropriate equimolar quantity of substituted 4-chlorobenzaldehyde (2 mmol), acetophenone (2 mmol) and fly ash based catalyst (0.75 g) have been taken in borosil tube and tightly capped. The mixture is exposed to microwave for 2-3 min in a microwave oven and then cooled at room temperature. The organic layer has been separated with dichloromethane which on evaporation yielded the solid product. The solid on recrystallization with benzene-hexane mixture gives glittering solid. The insoluble catalyst has been recycled by washing the solid reagent remained on the filter by ethyl acetate followed by drying in an oven at 100° C for 1 h. This recycled catalyst has been made reusable for further reactions. |
| 82% |
With sodium hydroxide In ethanol; water for 2h; |
|
| 82% |
Stage #1: (4-nitrophenyl)ethanone With sodium hydroxide In ethanol for 0.333333h; Cooling with ice;
Stage #2: benzaldehyde In ethanol at 20℃; |
|
| 80% |
With sodium hydroxide In ethanol; water at 0 - 20℃; |
|
| 80% |
With sodium hydroxide In methanol; water at 20℃; for 12h; Inert atmosphere; |
|
| 80% |
With potassium hydroxide In ethanol |
|
| 77% |
With sodium hydroxide In ethanol at 20℃; for 0.25h; |
Chalcones 8a-8f were synthesized as described in[24].
General procedure: A mixture of 10 mmol of 4-hydroxy- or 4-nitroacetophenone 6a or 6b, 10 mmol of benzaldehyde 7a-7c, and 20 mmol of sodium hydroxide was ground witha mortar and pestle for 15 min at room temperature.The mixture was treated with ice water, acidified with10% aqueous HCl to pH 2-4, and extracted with ether.The ether layer was washed with water, dried overanhydrous Na2SO4, and evaporated. The product waspurified by column chromatography on silica gel(n-hex ane-acetone, 6:4), followed by recrystalization. |
| 75% |
With sodium hydroxide In methanol; water at 20℃; for 2h; |
2.1. Synthesis
General procedure: The chalcones were synthesized employing Claisen Schmidt condensation (Fig. 1). Acetophenone derivatives were combined with an equimolar amount of benzaldehyde (Table 1). A 50% sodium hydroxide solution was used as basic catalyst and methanol as solvent [1]. All the reagents were analytical-reagent grade and were used without further purification. General procedure: In a flask equipped with a magnetic agitation and an ice bath, 20 mmol of the corresponding acetophenone and 50 mL of methanol were placed. Then, 5 ml of a 50% aqueous solution of sodium hydroxide and 20 mmol of benzaldehyde were added. The reaction mixture was preserved at room temperature for 2 h. After this time the precipitate was vacuum filtered and washed with ice-cold distilled water. |
| 75% |
With sodium hydroxide at 20℃; |
|
| 73.2% |
With sodium hydroxide In ethanol; water at 0 - 20℃; for 26h; |
1.1. General procedure for the synthesis of (E)-nitrochalcones (5-7)
General procedure: A solution of NaOH (6.7 mmol) in water (6 mL) cooledat 0° C with an ice bath, and ethanol (10 mL) was slowly added, the reaction flask was then removed from the ice bath and set at room temperature before the slow addition of the corresponding acetophenone (1-3) (10 mmol) after this, benzaldehyde (4) (10 mmol) was slowly added to the reaction mixture, which was left at room temperature with mechanical agitation for 2 hours, afterwards the reaction mixture was cooled at 0 °C for 24 hours. The solid products were filtrated from the crude mixture, washed with cold water and recrystallized with a dichloromethane/ethanol mixture. The crystals thus obtained were dried at 70 °C and properly stored at room temperature prior their physicochemical and spectroscopic characterizations. |
| 73% |
With carbon tetrabromide In neat (no solvent) at 60℃; for 28h; |
|
| 70% |
With 1-(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl)-4-phenyl-1H-1,2,3-triazole In ethanol at 100℃; for 20h; |
|
| 65% |
With montmorillonite KSF In neat (no solvent) at 170℃; for 3h; Sealed tube; Microwave irradiation; Green chemistry; |
3.2. General Procedure for Cross Aldol Condensations
General procedure: A mixture of the suitable aldehyde (1.0 mmol), acetophenone (1.0 mmol) and clay catalyst(240 mg) was warmed at 150 °C in a sealed tube under microwave irradiation, for 1 h. In the reactions involving solid starting materials, they were thoroughly mixed by grinding in a mortar before irradiation. The reaction mixture was diluted with hot ethanol (20 mL), the catalyst was filtered off, the solvent was evaporated and the residue was purified by crystallization (EtOH) for solid chalcones(compounds 3a-3d, 3f-3m, 3p-3ar) or by column chromatography (silica gel, ethyl acetate/hexanes) for oily chalcones (compounds 3e, 3o), to afford the pure final products. All yields were calculated from isolated products. Characterization data for previously unknown compounds are given below. For full characterization data, see the Supporting Information. |
| 63% |
With sodium hydroxide In ethanol for 24h; Ambient temperature; |
|
| 60% |
With potassium hydroxide |
|
| 44% |
With sodium hydroxide In ethanol; water Inert atmosphere; |
|
| 42.4% |
With sodium hydroxide In ethanol; water Heating; |
4.1.2. Synthesis and spectroscopic characterization of chalcones
General procedure: All syntheses were carried out in the same fashion. Each reaction was monitored by TLC for 24 h to determine when the starting materials had been consumed. All TLC analyses were run on Selecto Scientific flexible silica gel-coated plates containing a fluorescent indicator and were developed using a hexanes-ethyl acetate (4:1) solution as the eluent. The following procedure is representative of the synthesis of all chalcones (see [Chart 1] and [Chart 2] for structures): A 25-mL round-bottomed flask was charged with the appropriate derivatives of both acetophenone (3 mmol) and benzaldehyde (3 mmol), and mixed with 10 mL of 95% EtOH. The mixture was then stirred magnetically while being gently heated (in a 30 °C water bath) until both starting materials dissolved. In a separate flask, NaOH (3.5 mmol) was added to 10-mL of an ethanol-water (1:1) and the mixture was stirred magnetically until the solid dissolved. The NaOH solution was then added dropwise (using a Pasteur pipet) to the ethanolic solution of acetophenone and benzaldehyde described above. In most cases, the reaction mixture turned yellow and solidified within a few minutes. Ice water (2 mL) was added to the flask and the mixture was stirred vigorously. The solid was collected on a Hirsch funnel, washed with cold water, and air-dried overnight. The purity of the crude product was determined at this point using a combination of TLC analysis, melting point measurement, and 1H NMR spectroscopy. In case of an oily product, the reaction mixture was extracted with two 10-mL portions of CH2Cl2 and the organic phase was collected, dried over Na2SO4, and removed using a rotary evaporator. The purity of the oily product was then determined as described above. All impure products (solid or oil) were purified by column chromatography using Merck Silica gel (grade 60, 230-400 mesh) and 4:1 hexanes-ethyl acetate as eluent. In case of a solid, chromatographic separation was followed by recrystallization from either methanol or ethanol-water mixture. In all cases, the purity of the final product was checked again as described above; the spectral characteristics were found to be in good general agreement with those found in the literature.4 The organic chalcones prepared for this study were either pale-yellow solids or oils of the same color (as specified); the ferrocenyl analogs were reddish-orange solids or oils. For each of the reported compounds below, the 1H NMR data is presented as δ (multiplicity, integral ratio), and the IR data as νCO, νCC. The following % yield and physical data are for new chalcones prepared for this study. Data for other chalcones (not given below) have been reported elsewhere[4], [5] and [6] and are also available online as Supplementary data. |
| 25% |
Stage #1: benzaldehyde; (4-nitrophenyl)ethanone With sodium hydroxide In ethanol at 20℃; for 0.0833333h; Sealed tube;
Stage #2: With sodium hydroxide In ethanol; water |
|
|
With potassium hydroxide |
|
|
With hydrogenchloride |
|
|
With boron trifluoride; acetic acid |
|
|
With sodium hydroxide |
|
|
alkaline condensation; |
|
|
Stage #1: (4-nitrophenyl)ethanone With lithium hydroxide In ethanol at 25 - 30℃; for 0.583333h;
Stage #2: benzaldehyde In ethanol Further stages.; |
|
|
With sodium hydroxide In methanol; water at 20℃; for 18h; |
|
|
With sodium hydroxide In methanol at 20℃; for 0.333333h; |
General procedure for the preparation of ring substituted chalcones (3a-j)
General procedure: Chalcones were synthesized according to the previously described methodology29. A substituted acetophenone (5 mmol) and benzaldehyde(5 mmol) were dissolved in dry methanol (30 ml). To this methanolic solution, 5ml of sodium hydroxide (50%) was slowly added. Stirring was continued (20 min.-1 h) at room temperature and to neutralize the contents, 1N HCl was added. Reaction time taken for the completion of reactions is mentioned in Table.1. A mixture of ethyl alcohol and water was used for recrystallization. The synthetic procedure and reaction conditions for chalcones are illustrated in scheme 1. |
|
With sodium hydroxide In ethanol; water at 20℃; |
General procedure for the preparation of α,β-unsaturated ketones (1b-1k).
General procedure: A 50 mL round-bottomed flask was charged with the appropriate ketone (3.0 mmol), aldehyde (3.0 mmol) and 10 ml of 95% EtOH, to which a NaOH solution [3.5 mmol of NaOH in 10 mL of ethanol-water (1:1, v/v)] was added dropwise. The mixture was stirred at room temperature. In most cases, a precipitate produced after stirring for several hours. The solid was collected by filtration, washed with water and recrystallized from EtOH to get the products. In the cases that oily products were produced, the solvent of reaction mixture was removed by rotary evaporator, the residue was treated with water (20 mL) and extracted with CH2Cl2 (3×20 mL). The organic phase was dried over anhydrous Na2SO4, and solvent was removed by a rotary evaporator. The residue was purified by column chromatography with petroleum ether/ethyl acetate (15:1-5:1) as an eluent to give products. |
|
With hydrogenchloride; acetic acid at 20℃; for 12h; |
Synthesis
General procedure: The chalcone derivatives with nitro groups were synthesized by Claisen-Schmidt condensation in acid-catalysed reaction (Scheme 1) as nitro compounds were found to decompose in the base catalysed reaction. 0.02 mol of aldehyde and 0.02 mol of ketones (4-nitroacetophenone or 3-nitroacetophenone) were added to round-bottom flask containing 20 ml acetic acid saturated with HCl gas. The reaction mixture was then stirred at room temperature for 12 hrs. The progress of the reaction was monitored by TLC. On the completion of reaction, the contents were poured in ice cold water and the product was filtered. The solid obtained was washed with water till neutral to litmus. The crude chalcone was then dried and weighed and was recrystallized in chloroform-methanol (Furniss 1989) (Figs. 1, 2). In case of 4-N(CH3)2-4′-NO2, the contents of the reaction were neutralized with aq. NaOH before filtration. |
|
With sodium hydroxide In ethanol; water at 20℃; for 12h; |
Chalcones 2a-2d were prepared following the known proceduce:[7] benzaldehyde and NaOH were added to a solution of acetophenone in EtOH at room temperature. The mixture was stirred for 12 h, neutralized with diluted HCl, and extracted with EA. The organic layer was dried over Na2SO4 and the solvents evaporated. The residue was purified by flash column chromatography to give corresponding chalcones. |
Chemistry
Pharmaceutical Intermediates
Inhibitors/Agonists
Material Science
Life Science
For Research Only
100K+ Compounds
Competitive Price
1-2 Day Shipping
