Bi-functional modified-phosphate catalyzed the synthesis of α-α′-(EE)-bis(benzylidene)-cycloalkanones: Microwave versus conventional-heating

The impregnation of hydroxyapatite (HAP) by NaNO3 leads to a modified-hydroxyapatite which has a bi-functional acid-base property. Sodium-modified-hydroxyapatite (Na-HAP) efficiently catalyzed the cross-aldol condensation of arylaldehydes and cycloketones to afford α-α′-(EE)-bis(benzylidene)-cycloalkanones in good yields under microwave irradiation. Moreover, the methodology described in this paper provides a very easy and efficient synthesis carried out in water as the greenest available solvent under conventional heating. A comparison study between these two different modes of heating was investigated. The catalyst was easily recovered and efficiently re-used.

Cross-aldol condensation over sodium-modified-hydroxyapatite, as green heterogeneous catalyst, is described.Figure optionsDownload high-quality image (188 K)Download as PowerPoint slideResearch highlights▶ Hydroxyapatite is modified by sodium nitrate to give a bifunctional acid-base catalyst (Na-HAP). ▶ Na-HAP efficiently catalyzed the cross-aldol condensation of arylaldehydes and cycloketones to afford a series of α-α′-(EE)-bis(benzylidene)-cycloalkanones. ▶ A comparative study between two methods of heating (conventional heating and microwave irradiation) was achieved. ▶ The Na-HAP was easily recovered and efficiently re-used.