Try without any solvent, "Toda, F., et al., J. Chem. Soc. Perkin Trans. I, 1990, 3207".

This method is very simple and effective, Catalysis Communications 9 (2008) 315–316

Try out this procedure: 0.01 M acetophenone + 0.01 M aldehyde + 7.5 ml ethanol at 0-5 degree celsius. Then slowly add 5 ml of 70 % sodium hydroxide. Stir for three hours and allowed to stand overnight. Decompose in ice cold water , neutralize with dilute HCl and filter it.

Agree with Hema - I'm usually using 50% NaOH (aq) added to MeOH solution of acetophenone and aldehyde, then allow to stand overnight (use just a few mL of solvent and you'll see the chalcone salt precipitate). Then neutralize with 5% aq HCl.

You may require a catalytic amount of Alkali or a neat reaction without any solvent can be tried. Green Chem.,2004, 6, 227-31

first check reaction completion by HPLC if reaction is completed thn nutralise the reaction mixture, if no solid is forming thn distill maximum extent of solvent ,after that charge 3 times hexane and allow to stir at 0-5 degree centigrade. solid wl form

I produced hundreds of grams in 10 minutes using the 2 reagents in 1volume of ethanol with catalytic Ba(OH)2 under ultrasounds. Ba(OH)2 is dried 1 hour at 200°C. (Old publication of 1984 and many after)

The chalcone yield is 99+ %

In a 250 ml Erlenmeyer flask, prepare a solution of sodium hydroxide (4 g in 30 ml water and 30 ml of ethanol at 95 °). Cool the solution in an ice bath and add a mixture of 0.1 mol of acectophenone and 0.1 mol of benzaldehyde. Stir the mixture for an hour until a yellow oil formed. Rub the inside of the cold Erlenmeyer flask or add a crystal of chalcone. A yellow solid forms instantly, filter, dried and recrystallized in ethanol at 95 °.

Try the procedure below as reported by us (Ajani et al., Pak. J. Sci. Ind. Res.: Ser. A Phys. Sci. 2011, vol 54(2), pp 59-67)

To a solution of sodium hydroxide (2.5g) in water (20 mL), was added ethanol (10 mL) with continuous stirring until it cools down to room temperature. To this solution was added a mixture of appropriate ketone (14.15 mmol) and benzaldehyde (14.15 mmol or 28.30 mmol) drop-wisely with continuous stirring at room temperature for 30 min. The resulting solution formed colored precipitate which was filtered by suction, washed and recrystallized from appropriate solvent

Chalcones were synthesized by base catalyzed Claisen‐Schmidt condensation reaction of appropriately substituted acetophenones and aldehydes by known literature method.

A mixture of benzaldehyde derivatives (0.01 mol) and acetophenone derivatives (0.01 mol) was dissolved in 25 ml rectified spirit in a 100 ml round‐bottomed flask equipped with a magnetic stirrer. Then NaOH solution (10 ml, 10 %) was added drop wise to the reaction mixture on vigorous stirring for 30 minutes when solution became turbid. The reaction temperature was maintained between 20‐25 ˚C using a cold water bath on the magnetic stirrer. After vigorous stirring for 4‐5 hours, the reaction mixture was left to stand for overnight at refrigerator. The precipitate obtained was filtered, washed, dried in air and recrystallized from ethanol.

benzaldehyde( 10 gm) dissolved in 20 ml ethanol along with equivalent amount of acetaldehyde and few pallets of KOH, product starts forming within 5 mins, after over night stirring filter the light yellow crytalline products, washed twice or thrice with cold ethanol, pure final product.

As our colleague Hassan Abd El-Aal stated, the formation of chalcone is highly dependent on the amount of water present (he proposed the use of rectified spirit for this, ca. 70% of ethanol and 30% of water) in the reaction media since the elimination of hydroxylated intermediate should occur but this is a well known equilibrium reaction and the chalcone should be obtained through the displacement with the removal or absence of water in the media. Hence i strongly suggest to use absolute ethanolic solution of 50-70% of NaOH in order to precipitate the highest amount of chalcone with some of the above mentioned cold overnight precipitation procedures. Hope this helps in your research.

use potassium terbutoxide in THF, room temperature, overnight

You are trying to synthesis a chalcone from benzaldehyde (1eq) and acetophenone (1eq) in the presence of aqueous NaOH (40% w/w, 5 mL) it is stirred overnight in ethanol (amount of minimum). Then ıt is poured ice water and neutralization with 10% HCl.

Thank to all of you for your answers they really helped.

Want I basically did was place my reaction mixture in an ice-bath after the 16hrs of stirring.

Addition of acetophenone to NaOH sln (water and alcohol) in cold condition (~5-10 C), then we do the

benzaldehyde addition

Use the following method

2.2 g NaOH in 20 ml of water and 10 ml ethanol in Flask , cool the mixture in ice bath then pour 5.2 g of acetophenone start the stirrer , then added 4.4 ml of banzaldehyde , keep the temperature about 25oC and still the stirrer 2-3 h , finally leave the mixture in refrigerator overnight, collect the product by filtration

Most of other researchers here said already what the right procedures are. Better use aqueus 10% NaOH and also small quantity of methanol as reaction solvent. I use the icebath until addition of regeants is finished. Then i let it in r.t. Leave it stirring around 15 hours and filter off the precipitatre.Then put what is left in the fridge for further prepcipitation. If you do it that way the first precipitate (before fridge) will be much cleaner especially if you wash it with water.

follow up the official procedure which gives the best pure yield

Organic Syntheses, Vol. 2, p. 1 (1922); Coll. Vol. 1, p.78 (1941).

http://www.orgsyn.org/orgsyn/default.asp?formgroup=basenpe_form_group&dataaction=db&dbname=orgsyn

best regards

Please check this useful link

http://pubs.acs.org/doi/abs/10.1021/ed081p1345

Try with PEG 400 as a solvent

Take eq.amt of acetophenone add 10% of KOH (in PEG400) stirr for 10 min at Room temp and than add benzzaldehyde dropwise keep the reaction mixture at 40 degree temp or 30 min and workup the mixture in ice cold water keeep it for overnight you will get the product

try with thionyl chloride in ethanol and i tried it and succeed 100% and according to my article:

SYNTHESIS OF NEW FLUORINATED CHALCONE DERIVATIVE WITH ANTI-INFLAMMATORY ACTIVITY

try with solid pallet of NaOH.... i did more then 200 times... always done.. or use HCl gas..best to avoid impurities...

Chalcones can be prepared by an aldol condensation between benzaldehyde and acetophenone in the presence of sodium hydroxide as a catalyst. This reaction has been found to work without any solvent at all - a solid-state reaction.

See this article:

Toda, F., et al., J. Chem. Soc. Perkin Trans. I, 1990, 3207.

dear Shaanika you can try this reaction in methanolic KOH(3 equivalent by weight of acetophenone) and stirr for 24 hour.Inetially you dissolve acetophenone in methanol and put on ice bath for half an hour and after add aldehyde.

If the reaction stops at aldol reaction, then the product may be liquid. Check the TLC for the consumption of acetophenone. If there is no starting material go for heating with some more NaOH to eliminate water so that you can get chalcone

You can prepare chalcones by Caisen-Smith condensation of aldehyde with ketone in NaOH by stirring thenice cooling for 1 hr. the chalcones will separate out. Refer : Text book of practical Organic Chemistry A.I. Vogel,s .

Some time reaction mass require refluxing also

Use freshly distilled benzaldehyde?

Shiv Yadav - right (y need reflux it). one more method: reflux in i-PrOH with 5 drops of piperidine.

I am in total agreement with F Aqra. Based on Toda's paper, we prepared a huge number of chalcones in absence of solvent and found the reaction (a very simple procedure, by grinding using porcelain mortar and pestle) to be highly efficient (very fast), high yield, reduction of waste, etc. You may need to read both Toda's paper and my own (Mihigo et al., Bioorganic and Medicinal Chemistry, 2010, 18(7): 2463-2473).

Good luck

Use fresh distilled benzaldehyde and also take TLC at regular interval. When starting material finished, surely you will have product.

yes, Mihigo recommendation  is true.

I am totally agree with Dr. Mihigo.

U can add equivalent amounts of acetophenone (0.01mM) and benzaldehyde (0.01mM) were dissolved in methanol in ice bath for 10-20 minutes and then add 60% NaOH solution dropwise to it . After one hour a yellow solid precipitate is formed in the reaction check its TLC and filter, dried and recrystallized the product.

Try thionyl chloride in dry methanol under Ar

you can add equivalent amounts of acetophenone and benzaldehyde were dissolved in absolute ethanol in room temperature and then add 10% NaOH solution dropwise to it . After 4 hour a solid precipitate is formed in the reaction check its TLC and filter, dried and recrystallized the product.

Thank you so much Sir and Mam. I am done with equal amount of benzaldehyde and Acetophenone . But yield is very less . thanks all once again

please refer the following review

Article Chalcone: A Privileged Structure in Medicinal Chemistry

best regards

3% NaOH is very diluted, concentration should be raised up to 50%.

Reflux gives bad result Dr. Surendra, ( @surendra Babu Lagu ) room temperature or cooling are recommended

Preparation of chalcones needs high concentration of NaOH

Distilled acetophenone and aldehyde should be used as impurities present in reaction and temperature play a vital role in chemical reaction. You can try these methods

acetophenone (1 mmol) was taken in a 100 ml beaker in it equimolar amount of distilled benzaldehyde (minimum amount ethanol is added along with aldehyde) should be taken and heat to boiling temperature and then transfer the beaker to ice bath temperature should be of below zero degree and alkali (40 %; 2 ml) should be added drop wise and stirring should be done for 10- 15 min. It will give you dark to lemon yellow colour product which should be washed with dil HCl (1 ml in 20 ml water ( dil HCl should be of very less strength, other wise it will decrease the percentage yield of the product, yeah I agree it will take a lot of time but the current protocol)

yes follows the procedure suggested by Olayinka Oyewale Ajani....

To a solution of sodium hydroxide (2.5g) in water (20 mL), was added ethanol (10 mL) with continuous stirring until it cools down to room temperature. To this solution was added a mixture of appropriate ketone (14.15 mmol) and benzaldehyde (14.15 mmol or 28.30 mmol) drop-wisely with continuous stirring at room temperature for 30 min. The resulting solution formed colored precipitate which was filtered by suction, washed and recrystallized from appropriate solvent.

Hi everybody, we was working a lot of time in this area, but this method with water solution with of sodium hydroxide didn’t give pure compound (this method (50% NaOH) give satisfactory results in case of 2-hydroxy acetophenons at RT). Better method refluxing in EtOH (dry) with mol 3-5% of NaOH. Very nice method (its working on azoheterocycle and 3-acetylcoumarines)– refluxing in BuOH (sec-BuOH) aldehyde and ketone in presence of 3-5 drop of piperidine.

One my friend Varum Kumar give good procedure: LiOH in dry EtOH at RT, its were working also in acetophenone but didn't work on 2-ac-pyridine and 4-ac-pyridine.

To a solution of acetophenone (12 g, 0.1 mol) in ethanol (15 mL), benzeldehyde (10.6 g, 0.1 mol) was added. To this mixture aqueous potassium hydroxide (60%) was poured gradually with constant stirring and continues the stirring for 1.5 h. After adding, the mixture of potassium salt of chalcone was kept for 14-16 h at room temperature. The potassium salt of chalcone was separated by ice-cold hydrochloric acid (10%, 30 mL). The separated solid was filtered and washed with ice-cold water (2x50 mL) till the washing was neutral to litmus. Recrystallized the compound with ethanol and dried at room temperature.

The known literatures suggest the Claisen-schimdt condensation reaction to synthesize the chalcone derivatives......

For synthesis a chalcone use freshly distilled benzaldehyde and freshly distilled acetophenone in the presence of aq. ethanolic NaOH(2M) , Stirr it for long time till you get precipitate. I you do not get ppt. add 10% HCl till the PH =7.

Ref-Procedure is given book in Text bok of Practical Organic Chemistry by A.I.Vogel.

I used ammonium acetate. I was about 15 years ago and I might forget detailes. If I am not mistaken, I used benzene and Dinna-Stark

concentration of sodium hydroxide is very diluted

Try 3 ml of 60% NaOH. Add drop wise

in beginng you must chack the impurity of starting materials . becouse the benzaldehyde oxidation to benzoic acid . then used a method of synthesis in the following link https://labmonk.com/synthesis-of-chalcone-from-benzaldehyde-and-acetophenone

Many chalcons can be prepared by using aromatic aldehydees as part chloro aniline , para anisedine ..ect, with the variety of ketones as acetone , acetophenone or cyclic ketone as cyclohexanone or cyclopentanone in ethanol in presence of piperidine or sodium methoxide 10% (2_3) drop in each case all the mixture refluxed 4 hours.We can use alkaline medium of 10%NaOH 5 ml ,stirring ,3 hour followed by acidification by HCl

the problem is methonal is un stable for this reaction try pure non denatured ethanol.

First add your aldehyde to half amount of solvent then add your alkaline sollution (mixture 1) and stir for some time (around 10 minutes) simultainously add your ketone to the remaining half of the solvent (mixture 2)and mix throughly.

After stiring mix both and continue stiring till starting material spot is no linger veseable on tlc. (your reaction timr will be dependent of thr strength of yout alkaline solution).

Why LDA cannot be used as base in this synthesis

What is characterization technique rather than NMR please?