ChemInform Abstract: Acetals and Vinyl Ethers of Unsaturated Aldehydes and Ketones in New Syntheses of Heterocyclic Compounds. Part 11. Condensation of Methyl Ketones and 1,3-Diketones with Benzaldehydes and Formanilides in Triethyl Orthoformate in the Pr

ChemInform ◽  
2000 ◽  
Vol 31 (38) ◽  
pp. no-no
Author(s):  
E. P. Olekhnovich ◽  
S. L. Boroshko ◽  
G. N. Borodkin ◽  
V. I. Kucher ◽  
L. P. Olekhnovich
Keyword(s):  
Heterocyclic Compounds ◽  
Triethyl Orthoformate ◽  
Methyl Ketones ◽  
Vinyl Ethers ◽  
Unsaturated Aldehydes ◽  
Aldehydes And Ketones

AN ULTRASOUND MEDIATED GREEN SYNTHESIS OF 2-PYRAZOLINE DERIVATIVES

2021 ◽  
pp. 36-39
Author(s):  
Shrivastava Birendra ◽  
Upasna Upasna ◽  
Arora Satish Chander
Keyword(s):  
Acetic Acid ◽  
Green Synthesis ◽  
19Th Century ◽  
Heterocyclic Compounds ◽  
Unsaturated Aldehydes ◽  
Aldehydes And Ketones ◽  
The 19Th Century

Pyrazolines are prominent nitrogen-containing heterocyclic compounds and therefore, various procedures have been worked out for their synthesis. After the pioneering work of Fischer and Knoevenagel in the 19th century, the reaction of α, β-unsaturated aldehydes and ketones with phenylhydrazine in acetic acid by reuxing became one of the most popular methods for the preparation of 2-pyrazolines. Aseries of substituted 2- pyrazolines was synthesized by ultrasound irradiated method to nd out cleaner/ greener approaches.

scholarly journals Theoretical Insight into the Reversal of Chemoselectivity in Diels-Alder Reactions of α,β-Unsaturated Aldehydes and Ketones Catalyzed by Brønsted and Lewis Acids

Organics ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 38-49
Author(s):  
Lakhdar Benhamed ◽  
Sidi Mohamed Mekelleche ◽  
Wafaa Benchouk
Keyword(s):  
Lewis Acids ◽  
Major Product ◽  
Diels Alder ◽  
Unsaturated Ketone ◽  
Unsaturated Aldehydes ◽  
Aldehydes And Ketones ◽  
Theoretical Insight ◽  
Insight Into ◽  
Good Agreement

Experimentally, a reversal of chemoselectivity has been observed in catalyzed Diels–Alder reactions of α,β-unsaturated aldehydes (e.g., (2E)-but-2-enal) and ketones (e.g., 2-hexen-4-one) with cyclopentadiene. Indeed, using the triflimidic Brønsted acid Tf2NH as catalyst, the reaction gave a Diels–Alder adduct derived from α,β-unsaturated ketone as a major product. On the other hand, the use of tris(pentafluorophenyl)borane B(C6F5)3 bulky Lewis acid as catalyst gave mainly the cycloadduct of α,β-unsaturated aldehyde as a major product. Our aim in the present work is to put in evidence the role of the catalyst in the reversal of the chemoselectivity of the catalyzed Diels–Alder reactions of (2E)-but-2-enal and 2-Hexen-4-one with cyclopentadiene. The calculations were performed at the ωB97XD/6-311G(d,p) level of theory and the solvent effects of dichloromethane were taken into account using the PCM solvation model. The obtained results are in good agreement with experimental outcomes.

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