ketone carbonyl
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Author(s):  
Lucas Barbosa ◽  
Tiago da Silva ◽  
Michelle Rezende ◽  
Bianca da Silva ◽  
Rodrigo Guzzo ◽  
...  

In this work, the combined use of p-sulfonic acid-calix[n]arene and microwave energy to hydrolyze the 1,3-dioxolane ketal of isatin was evaluated with excellent results. This is the first time that p-sulfonic acid-calix[n]arene has been used as the catalyst in a ketal hydrolysis reaction and the deprotection of the ketone carbonyl of isatin is reported. The presence of 2.5 mol% of p-sulfonic acid-calix[4,6]arene at 160 ºC resulted in over 96% conversion of this ketal in 10 min, with the additional advantage of using water as a solvent. This catalytic system (aqueous phase containing p-sulfonic acid-calix[4]arene) was reused for five consecutive cycles, with a conversion above 96% maintained. This reusable system is not practicable using p-toluenesulfonic acid and p-hydroxybenzenesulfonic acid as catalysts since both are extracted to the organic phase with the reaction product. The hydrolysis of 1,3-dioxolane ketal of isatins with different substituents (CH3, I, Br, Cl, F, NO2) in the aromatic ring was also evaluated. The protecting group of 5-methyl-isatin was removed with 73% conversion using 2.5 mol% of p-sulfonic acid-calix[4]arene at 160 ºC for 5 min. In contrast, the ketal of 5-nitro-isatin reached 80% conversion using the same conditions after 40 min.


Author(s):  
Beiye Yang ◽  
Jianzheng Huang ◽  
Shuang Lin ◽  
Qingyi Tong ◽  
Zeyu Yao ◽  
...  

Hyperbeanone A (1), a novel 5,6-seco-polycyclic PPAP derivative characterized by an undescribed benz[f]indene-1,9(4H)-dione ring system fused to a tricyclic γ-lactone unit via a ketone carbonyl, was isolated from the aerial parts of Hypericum beanii.


2020 ◽  
Vol 11 (2) ◽  
pp. 9405-9419

Radiation damage and reaction mechanism of product formation due to γ-irradiation in high-density polyethylene (HDPE) have been studied by Fourier transform infrared (FTIR), UV-vis spectroscopic, and x-ray diffraction (XRD) techniques. A Co60gamma source (with a dose rate of 1.707 kGy/hr) has been used up to the total dose of 570 kGy. There are dose-dependent changes in the polymer. The optical band gap decreases with the increase of the γ-irradiation dose. Formations of unsaturation centers have been observed. FTIR observed that a lower dose of γ-irradiation induces the formation of an unsaturated (-C=C-) group and a ketone carbonyl group. Breaking of the C-H bond is more frequent than the breaking of the C-C bond in irradiated HDPE. Crosslinking dominates over chain scission (breaking of C-C bond of the main chain) at a lower dose (100 kGy). There has been no significant influence of γ-irradiation on the crystalline structure, although crystalline size decreases. Mechanisms of the formation of alkyl, allylic, and polyenyl radicals have been investigated.


ACS Catalysis ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 9009-9014 ◽  
Author(s):  
Minh Duy Vu ◽  
Mrinmoy Das ◽  
Aoxin Guo ◽  
Zi-En Ang ◽  
Miloš D̵okić ◽  
...  

2018 ◽  
Vol 74 (10) ◽  
pp. 1463-1466 ◽  
Author(s):  
Dáire Gibbons ◽  
Ganapathi Emandi ◽  
Mathias O. Senge

The title compound, C11H9NOS, was obtained in an improved yield compared to previous literature methods. The molecule is essentially planar with a maximum deviation of 0.085 Å from the mean plane through all non-H atoms. There is directive intermolecular hydrogen bonding in the form of N—H...O hydrogen bonds with a distance of 2.889 (3) Å between the pyrrole amine and the ketone carbonyl O atom. The resulting hydrogen-bonding network defines a ribbon parallel to the a axis. These ribbons form offset stacks along the b axis.


ChemInform ◽  
2009 ◽  
Vol 40 (10) ◽  
Author(s):  
Jing-Qian He ◽  
Daisuke Shibata ◽  
Chihaya Ohno ◽  
Sentaro Okamoto
Keyword(s):  

2008 ◽  
Vol 49 (47) ◽  
pp. 6724-6727 ◽  
Author(s):  
Jing-Qian He ◽  
Daisuke Shibata ◽  
Chihaya Ohno ◽  
Sentaro Okamoto
Keyword(s):  

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