15818-09-4

Upstream product

• 104-87-0 4-methyl-benzaldehyde 
• 123-54-6 acetylacetone 
• 41002-50-0 4-acetoxy-3-penten-2-one 
• 40739-81-9 p-tolualdehyde p-toluenesulfonylhydrazone 

Downstream Products

• 120811-10-1 5-acetyl-2-amino-6-methyl-4-(4-methyl-phenyl)-4H-pyran-3-carbonitrile 
• 120811-05-4 3-acetyl-5-amino-6,6-dicyano-2-methyl-4,7-bis(p-methylphenyl)-6,7-dihydro-4H-pyrano<2,3-b>pyridine 
• 119757-21-0 4,4-Dimethoxy-3-[1-p-tolyl-meth-(E)-ylidene]-pentan-2-one 
• 582333-62-8 3-[1,8]naphthyridin-2-yl-4-p-tolyl-but-3-en-2-one 
• 1049806-67-8 (2S,3S)-ethyl 4-acetyl-5-methyl-3-p-tolyl-2,3-dihydrofuran-2-carboxylate 

Relevant academic research and scientific papers

Accelerating the optimization of enzyme-catalyzed synthesis conditionsviamachine learning and reactivity descriptors

Enzyme-catalyzed synthesis reactions are of crucial importance for a wide range of applications. An accurate and rapid selection of optimal synthesis conditions is crucial and challenging for both human knowledge and computer predictions. In this work, a

Cross-linked polystyrene-TiCl4 complex as a reusable Lewis acid catalyst for solvent-free Knoevenagel condensations of 1,3-dicarbonyl compounds with aldehydes

Cross-linked polystyrene copolymer beads with the average particle size in the range of (50–80 mesh size) were prepared by a new method, characterized and functionalized with titanium tetrachloride to afford the corresponding polystyrene?titanium tetrachloride complex in one step reaction and characterized by FT-IR, UV, TGA, DSC, XRD, SEM, BET. This polymer metal complex (PS/TiCl4) was used as a heterogeneous, recoverable, reusable Lewis acid for solvent-free Knoevenagel condensations of 1,3-diketones with aromatic aldehydes under green and mild conditions. The rate of reactions was found to decrease with an increasing percentage of crosslinking and the mesh size of the copolymer beads. This complex showed good stability and catalytic activity in the Knoevenagel reactions.

Enzyme Promiscuity as a Remedy for the Common Problems with Knoevenagel Condensation

A new protocol based on lipase-catalyzed tandem reaction toward α,β-enones/enoesters is presented. For the synthesis of the desired products the tandem process based on enzyme-catalyzed hydrolysis and Knoevenagel reaction starting from enol acetates and aldehyde is developed. The relevant impact of the reaction conditions including organic solvent, enzyme type, and temperature on the course of the reaction was revealed. It was shown that controllable release of the active methylene compound from the corresponding enol carboxylate ensured by enzymatic reaction diminishes significantly the formation of the unwanted co-products. Furthermore, this protocol was extended by including a second tandem chemoenzymatic transformation engaging various aldehyde precursors. After a careful optimization of the reaction conditions, the target products were obtained with yields up to 86 % and with excellent E/Z-selectivity.

Corrigendum to: Enzyme Promiscuity as a Remedy for the Common Problems with Knoevenagel Condensation (Chemistry – A European Journal, (2019), 25, 43, (10156-10164), 10.1002/chem.201901491)

In the published paper, there is a mistake in the labelling of compounds in Figure. A corrected version of that Figure appears below. The authors apologise for the mistake. Figure (Figure presented.) Unsaturated 2,4-pentanediones obtained by enzyme-catalyzed tandem Knoevenagel reaction. Reaction conditions: aldehyde (1 mmol), 4-acetoxy-3-penten-2-one (5 a, R1=R2=R3=Me) (3 mmol), and PPL (100 mg) in tert-butyl alcohol/ 5 % H2O v/v (2 mL) for 72 h at 20 °C, 200 rpm. [a] With vinyl acetate. [b] With ethyl β-styrylcarbonate. [c] With styryl acetate.

Construction of Multi-Substituted Benzenes via NHC-Catalyzed Reactions of Carboxylic Esters

A carbene-catalyzed ester activation reaction for the synthesis of multi-substituted benzenes is developed. Tetra-substituted benzene compounds are efficiently synthesized through this methodology. Compared with aldehyde substrates used in previous reports, the ester substrates used here are much more readily available and inexpensive. In addition, the TEMPO oxidant used here is more inexpensive than the quinones commonly used in related carbene-catalyzed reactions.

A facile synthesis of trisubstituted alkenes from β-diketones and aldehydes with AlCl3 as catalyst

Preparation of trisubstituted alkenes from low-activity β-diketones and aldehydes with aluminum chloride as catalyst has been studied. The frequently used catalyst AlCl3 is used for the first time to promote this condensation. The procedure is a convenient, low toxicity, and highly efficient method for industrial synthesis of trisubstituted alkenes in high yield. Springer Science+Business Media B.V. 2011.

Biocatalytic Knoevenagel reaction using alkaline protease from Bacillus licheniformis

BLAP (alkaline protease from Bacillus licheniformis) was used as a biocatalyst in the Knoevenagel condensations of aromatic, hetero-aromatic and α;β-unsaturated aldehydes with less reactive acetylacetone or ethyl acetoacetate. The reactions were performed in organic solvent in the presence of water. The functionalized trisubstituted alkenes and α,β,γ, δ-unsaturated carbonyl compounds could be obtained in moderate to good yields with E/Z selectivities up to >99:1. This biocatalytic reaction provided an alternative pathway for Knoevenagel condensation, which also demonstrates a novel case of unnatural activity of existing enzymes.

An efficient iodine-catalysed Knoevenagel condensation reaction in the presence of acetic anhydride

A mild, simple and efficient iodine catalysed system has been developed for the Knoevenagel condensation of 1,3-dicarbonyl compounds with various aromatic aldehydes in the presence of acetic anhydride. The reaction gave good to excellent yields for a broad range of substrates.

A simple method for the preparation of functionalized trisubstituted alkenes and α,β,γ,δ-unsaturated carbonyl compounds by using natural amino acid l-tryptophan

Primary natural amino acid l-tryptophan was used, for the first time, as a catalyst in Knoevenagel condensations of aliphatic, aromatic, hetero-aromatic and α,β-unsaturated aldehydes with less reactive acetylacetone and ethyl acetoacetate. The reactions were carried out at room temperature and gave good yields. It is a convenient entry for preparation of functionalized trisubstituted alkenes and α,β,γ,δ-unsaturated carbonyl compounds.

Catalysis by L-lysine: A green method for the condensation of aromatic aldehydes with acidic methylene compounds in water at room temperature

The condensation of aromatic aldehydes with acidic methylene compounds such as ethyl benzoylacetate, 2,4-pentanedione and dimedone proceeded efficiently in pure water in the presence of L-lysine at room temperature. Interestingly, there are two different