Carbonyl carbon seems to be less electrophilic in Imidazole-4-carbaldehyde.

I have used the following procedure to obtain 5-hydroxymethyl-furfurylideneacetophenone:

0.05 mole of aldehyde dissolved in 10 ml of methanol. With vigorous stirring, 0.05 mol (6 ml of acetophenone is added. Continuing stirring, 0.0025 mol of KOH (0.85 ml of 15% solution) is added and then mixture was stirred for 3.5 hrs. Then, it was acidified with 10% acetic acid until precipitation occurrs. A small portion of water was added and the mixture left at (-5 degC) to precipitate.

I give my very old, being 23 y.o paper describing two methods for this Claisen-Schmidt condensation.

Organic Procedures & Preparations International, 1993, 25, 353. If you wish, I can send it to you, but privately only (copyright reasons)

Good luck

Jarosław Lewkowski

Thank you Saikat for your suggestion. I will go through the article.

Thank you Jarosław. I had use KOH pellets too. However it did not work with Imidazole-4-carbaldehyde. You could send me DOI number as I have access to this journal. I will try the conditions you worked with. 

Could you try neat reaction with KF-alumina (basic alumina); heat with microwaves or expose to ultrasound?

I would try that as it is simple and not too time consuming. Let me know if it works?

Best wishes.

Vathan

DOI: 10.1080/00304949309457976

All the best,

Jarosław

Dear

Vathan Kumar

Academia Sinica

You may try using  microwave with suitable support like basic Alumina.

Good luck

Prof. Dr. Talaat El-Emary