Facile one-pot green synthesis of tetrahydrobiphenylene-1,3-dicarbonitriles in aqueous media under ultrasound irradiation

Synthesis of bis-spiro piperidines using nano γ-alumina supported Sb(v) under ultrasonic irradiation at room temperature conditions

Group VA metalloid ion Lewis acids, Sb(v) was identified as a highly potent catalyst for the one-pot three-component synthesis of bis-spiro piperidine derivatives. The reaction was performed using amines, formaldehyde, and dimedone under ultrasonic irradiation at room temperature. The strong acidic property of the nano γ-alumina supported antimony(v) chloride plays a key role in accelerating the rate of the reaction and initiates the reaction smoothly. The heterogeneous nanocatalyst was fully characterized by FT-IR spectroscopy, XRD, EDS, TGA, FESEM, TEM, and BET techniques. Also, the structures of the prepared compounds were characterized by ¹H NMR and FT-IR spectroscopies.

Ag₂O on ZrO₂ as a Recyclable Catalyst for Multicomponent Synthesis of Indenopyrimidine Derivatives

We describe the synthesis of silver loaded on zirconia and its use as an efficient catalyst for a one-pot three-component reaction to synthesize 11 indenopyrimidine derivatives, of which 7 are new compounds. The procedure involves substituted benzaldehydes, indane-1,3-dione, and guanidinium hydrochloride, with ethanol as solvent. The proposed green protocol at room temperature is simple and efficient, giving excellent yields (90⁻96%) in short reaction times (<30 min). The protocol works well according to the green chemistry principles with respect to high atom economy, no need for column separation, and reusability of the catalyst, which are attractive features. XRD, TEM, SEM, and BET analysis were used to characterize the catalyst materials.