Efficient and one-pot synthesis of 1,8-dioxo-octahydroxanthenes was described by Knoevenagel condensation, Michael addition and cyclodehydration of dimedone. This reaction was carried out through condensation of dimedone and various aromatic aldehydes in the presence of task-specific Brønsted acidic ionic liquid under solvent free conditions. The catalyst could be recycled five times without si...

A sustainable Knoevenagel condensation of a series of aldehydes with malononitrile and ethyl cyanoacetate is described. The process is based on the combination of microwave activation and hydroxyapatite catalysis under solvent-free conditions. Products are obtained in and high yields after short reaction times. The effects of the specific surface of porous calcium hydroxyapatite and microwave a...

A practical protocol for the preparation of (5Z)-2-alkylthio-5-arylmethylene-1-methyl-1,5-dihydro-4H-imidazol-4-one derivatives is reported. The new compounds were obtained in good yield and stereoselectivity in two steps, namely a solvent-free Knoevenagel condensation under microwave irradiation, followed by an S-alkylation reaction with various halogenoalkanes.

The nitrogen-substituted delaminated ITQ-2 zeolite was found to be a highly active and recyclable catalyst for the Knoevenagel condensation of bulky aromatic aldehydes with ethyl cyanoacetate which cannot take place over the base sites placed within the micropores of conventional zeolites due to spatial limitations.

Unique three-component self-assembly of a cis-blocked 90° Pd(II) acceptor with a mixture of tri- and tetra-imidazole donors led to the self-sorting of a Pd7 molecular boat with an internal nanocavity, which catalyses the Knoevenagel condensation of a series of aromatic aldehydes with 1,3-dimethylbarbituric acid and Meldrum's acid in aqueous media.

The one-step cyclocondensation of substituted isoflavones with cyanothioacetamide in the presence of sodium hydroxide gave an array of 3-cyano-5,6-diaryl pyridine-2(1H)-thiones in good yields. The procedure involves base-mediated ring opening of the isoflavones and subsequent Knoevenagel condensation between the 1,3-dicarbonyl intermediate generated from the isoflavones and cyanothioacetamide, ...

Correction for ‘A review of the recent progress on heterogeneous catalysts Knoevenagel condensation’ by Jimmy Nelson Appaturi et al., Dalton Trans., 2021, 50, 4445–4469, DOI: 10.1039/d1dt00456e.

We disclose herein a highly enantioselective de novo-synthesis of chiral 1-cyclopentenyl-α-keto esters starting from a simple bis-silyl-1,3-dienediolate and α,β-unsaturated aldehydes via a domino vinylogous Michael-intramolecular Knoevenagel-type condensation. The cyclopentenes proved to be highly versatile and were readily converted into various structural motifs.

Nitrogen-containing carbon nanotubes (NCNT) are effective re-usable solid base catalysts, their activity for a Knoevenagel condensation being related to the amount of pyridinic nitrogen incorporated in the NCNT structure, which could be tuned by the synthesis parameters of the catalyst.

(diacetoxyiodo)benzene has been used as an efficient catalyst for an improved and rapid one-pot synthesis of biscoumarin derivatives in excellent yield under reflux condition using water as a environmentally benign reaction medium. this aqua mediated knoevenagel condensation of various aromatic and hetero-aromatic aldehydes with 4-hydroxycoumarin using catalytic amount of (diacetoxyiodo)benzene...