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Organic Synthesis
Published in Suresh C. Ameta, Rakshit Ameta, Garima Ameta, Sonochemistry, 2018
Chetna Ameta, Arpit Kumar Pathak, P. B. Punjabi
Calvino et al. (2005) synthesized chalcones under sonochemical irradiation by Claisen-Schmidt condensation between benzaldehyde and acetophenone. Two basic activated carbons (Na and Cs-Norit) have been used as catalysts. A significant enhancement in the yield was observed, when the carbon catalyst was activated under ultrasonic waves. This green method (combination of alkaline-doped carbon catalyst and ultrasound waves) has been applied for the synthesis of several chalcones with excellent activities and selectivity.
N-Polyheterocycles
Published in Navjeet Kaur, Metals and Non-Metals, 2020
Mathew et al. [25] synthesized (2E)-1-(1H-benzimidazol-2-yl)-3-phenylprop-2-en-1-ones. o-Phenylenediamine reacted with lactic acid to afford 2(α-hydroxyethyl)benzimidazole which was oxidized in the presence of potassium dichromate to yield 2-acetyl-benzimidazole. The chalcones were produced by Claisen-Schmidt condensation of 2-acetyl benzimidazole with appropriate aldehydes in the presence of a base (Scheme 3).
Mechanochemical synthesis of indolyl chalcones with antiproliferative activity
Published in Green Chemistry Letters and Reviews, 2022
Zuzana Kudličková, Martin Stahorský, Radka Michalková, Mária Vilková, Matej Baláž
Chalcones (1,3-diarylprop-2-en-1-ones) are widely distributed in plants, acting as precursors for the biosynthesis of flavonoids and isoflavonoids. Thanks to easy derivatization and synthesis, chalcones are used as an effective template in medicinal chemistry for drug development. The natural and synthetic chalcones have shown numerous interesting biological activities such as anticancer (17–19), antibacterial (20), antiviral (21), and anti-inflammatory (22). Many techniques and processes have been reported with various catalysts and reaction conditions for the synthesis of these medically important compounds: Claisen–Schmidt condensation, Suzuki reaction, Heck reaction, Friedel–Crafts acylation, Wittig reaction, and Photo-Fries rearrangement of phenyl cinnamate (23). The Claisen–Schmidt condensation between acetophenone and aryl aldehyde derivatives, using either strong base or acid as catalyst, is the most frequently used reaction in chalcone preparation. The disadvantage of these reactions is the long duration and often the formation of complex reaction mixtures containing also, in addition to the expected product, by-products and starting materials. The yield could vary ranging from 10 to near 100% conversion, depending on reactants and catalyst (23). The classical Claisen–Schmidt reaction is generally carried out using aqueous sodium or potassium hydroxide at 50 °C over several hours (24).
Synthesis, spectral investigation, thermal, molecular modeling and bio-molecular docking studies of a thiazole derived chalcone and its metal complexes
Published in Journal of Coordination Chemistry, 2020
The structure of the ligand and Zn(II) complex were further supported by their NMR spectral data. The 1H NMR spectrum of 2-acetylthiazole shows an intense peak at 2.4 ppm corresponding to acetyl group bonded to the thiazole ring. The spectrum of HPTP (Figure S3, supplementary material) has no peaks related to aldehyde or acetyl moiety, confirming the chalcone formation via Claisen-Schmidt condensation. The ethylinic proton adjacent to carbonyl group displays a peak at 5.811 ppm (d, 1H, J = 1.6 Hz). The spectral shift for the proton is far from (–C = O) group at 7.573 ppm (d, 1H). A peak due to –OH moiety of thiazole-derived chalcone ligand is a singlet (10.281 ppm). The multiplets at 8-8.25 ppm are assigned to protons on the heterocyclic ring close to -C = N linkage. Other aromatic proton peaks were between 6.506 to 7.55 ppm [28]. {1H NMR (400 MHz, DMSO-d6), δ (ppm): 10.281 (1H, Ar-OH); 8.076-8.256 (m, 1H); 7.573 (d, 1H, J = 1.6 Hz); 7.550 (t, 2H, J = 1.6 Hz); 6.802 (d, 1H, J = 14 Hz); 6.506 (t, 2H, J = 10 Hz), 5.8 (d, 1H, J = 1.6 Hz)}.
Synthesis of thiazolylidenethiazoloquinazolinone hybrids from monocarbonyl curcumin analogues. Characterization, bio-evaluation and DFT study
Published in Journal of Sulfur Chemistry, 2022
Soufiane Benreka, Fatima-Zohra Zradni, Fatiha Madi, Gilbert Kirsch, Souad Kasmi-Mir
Briefly, substituted Bis(arylidene)Cyclohexanone (BAC) 2 were prepared in good-to-excellent yields (80-92% yield) under basic conditions by the Claisen Schmidt condensation method, a key intermediate in the synthesis of the target hybrid derivatives D1-D12. The second step is an aza-Michael addition of thiourea to Bis(arylidene)Cyclohexanone 2 under similar basic conditions to give an intermediate, which can undergo intramolecular cyclization by attacking the carbonyl group to produce intermediate 3.