2348-77-8Relevant articles and documents
Promotion of the chromium carbene Doetz annulation reaction under sonochemical and dry state adsorption conditions
Harrity, Joseph P. A.,Kerr, William J.,Middlemiss, David
, p. 5565 - 5576 (1993)
The chromium carbene Doetz annulation reaction proceeds very rapidly in the presence of ultrasound giving good yields of quinone product on oxidative workup. Moreover, the yield of annulated product has been improved by adsorbing the reagents onto silica and heating at moderate temperatures. Both these modifications have proved to be successful for a variety of complexes and alkynes.
Promotion of the chromium carbene dotz annulation reaction under dry state adsorption conditions
Harrity,Kerr,Middlemiss
, p. 2995 - 2998 (1993)
The chromium carbene annulation reaction has been carried out in the solid-state by adsorption of the reagents onto silica, neutral alumina and anhydrous magnesium sulphate. The reaction rate and product yield are examined.
Synthesis of aryl substituted quinones as β-secretase inhibitors: Ligand-free direct arylation of quinones with aryl halides
Wang, Dawei,Ge, Bingyang,Yang, Shuyan,Miao, Hongyan,Ding, Yuqiang
, p. 1615 - 1621 (2014)
The simple ligand-free direct arylation of quinones with aryl halides applying Pd(OAc)2as a catalyst in accordance with Heck reaction was studied. This reaction provided a simple and efficient synthetic approach to efficient inhibitors of β-secretase aryl-substituted quinones.
Oxidative Dearomatization of Phenols and Polycyclic Aromatics with Hydrogen Peroxide Triggered by Heterogeneous Sulfonic Acids
Pancrazzi, Francesco,Maestri, Giovanni,Maggi, Raimondo,Viscardi, Rosanna
supporting information, p. 5407 - 5414 (2021/10/25)
We report herein a method for the oxidative dearomatization of phenols and bare polycyclic arenes into the corresponding quinoid derivatives using hydrogen peroxide. The reaction is catalyzed by sulfonic acids and best results were achieved using heterogenized species. The best results using phenols were achieved using a hybrid material, namely a perfluorinated polymer functionalized with sulfonic acid groups supported on silica. The dearomatization of polycyclic aromatic hydrocarbons performed better using the polymeric acid catalyst. These methods operate under mild conditions, using mild and benign oxidants and thus minimizing the formation of waste.
Ruthenium(II)- and Palladium(II)-catalyzed position-divergent C–H oxygenations of arylated quinones: Identification of hydroxylated quinonoid compounds with potent trypanocidal activity
Gontijo, Talita B.,de Carvalho, Renato L.,Dantas-Pereira, Luiza,Menna-Barreto, Rubem F.S.,Rogge, Torben,Ackermann, Lutz,da Silva Júnior, Eufranio N.
, (2021/06/01)
A diversity-oriented synthesis of hydroxylated aryl-quinones via C–H oxygenation reactions and their evaluation against Trypanosoma cruzi, the etiological agent of Chagas disease, was accomplished. With the use of ruthenium(II)- or palladium(II)-based cat
Palladium-catalysed synthesis of arylnaphthoquinones as antiprotozoal and antimycobacterial agents
Kalt, Marc-Manuel,Schuehly, Wolfgang,Saf, Robert,Ochensberger, Sandra,Solnier, Julia,Bucar, Franz,Kaiser, Marcel,Presser, Armin
supporting information, (2020/10/06)
Malaria and tuberculosis are still among the leading causes of death in low-income countries. The 1,4-naphthoquinone (NQ) scaffold can be found in a variety of anti-infective agents. Herein, we report an optimised, high yield process for the preparation o
Palladium-catalyzed arylation of 1,4-naphthoquinones with aryl iodides and its synthetic application to the benzo[b]phenanthridine skeleton
Akagi, Yusuke,Komatsu, Toshiya
supporting information, (2020/10/02)
We report a Pd-catalyzed arylation of 1,4-naphthoquinones with aryl iodides. This reaction shows excellent functional group tolerance and high regioselectivity when using nonsymmetric 1,4-naphthoquinone. Furthermore, the resulting 2-aryl-1,4-naphthoquinon
Activated Carbon-Promoted Dehydrogenation of Hydroquinones to Benzoquinones, Naphthoquinones, and Anthraquinones under Molecular Oxygen Atmosphere
Kim, Sanghun,Matsubara, Ryosuke,Hayashi, Masahiko
, p. 2997 - 3003 (2019/03/08)
We found that the activated carbon-molecular oxygen system promotes the conversion of hydroquinones to benzoquinones, naphthoquinones, and anthraquinones, which are often found in natural products and pharmaceuticals. In particular, the one-pot synthesis of naphthoquinones and anthraquinones involving a Diels-Alder reaction is a useful protocol for this purpose.
NHC-Catalyzed Dual Stetter Reaction: A Mild Cascade Annulation for the Syntheses of Naphthoquinones, Isoflavanones, and Sugar-Based Chiral Analogues
Mitra, Rajendra N.,Show, Krishanu,Barman, Debabrata,Sarkar, Satinath,Maiti, Dilip K.
, p. 42 - 52 (2019/01/10)
The N-heterocycle carbene (NHC)-catalyzed dual Stetter cascade reaction is discovered through coupling of β-nitrostyrene with phthalaldehyde under mild conditions to furnish valuable aryl-naphthoquinones. The generality of the new reaction is validated through the development of a C-C and O-C bond forming Stetter cascade reaction using salicylaldehydes to obtain functionalized dihydroisoflavanones. The mild NHC organocatalysis is successfully employed for the construction of optically pure sugar-based naphthoquinones and dihydroisoflavanones. Herein, NHC is found as a unique and powerful organocatalyst to construct homoatomic C-C cross-coupling, heteroatomic O-C bond formation, and cascade cyclization utilizing NO2 as a leaving group at ambient temperature. A mechanistic pathway of the new metal-free catalysis is predicted on the basis of our ESI-MS study of the ongoing reaction and literature.
Comprehensive evaluation of antioxidant effects of Japanese Kampo medicines led to identification of Tsudosan formulation as a potent antioxidant agent
Sato, Naoko,Li, Wei,Takemoto, Hiroaki,Takeuchi, Mio,Nakamura, Ai,Tokura, Emi,Akahane, Chie,Ueno, Kanako,Komatsu, Kana,Kuriyama, Noriko,Onoda, Toshihisa,Higai, Koji,Koike, Kazuo
, p. 163 - 172 (2018/11/06)
Oxidative stress due to the overproduction of reactive oxygen species plays an important role in the pathogenesis of various diseases. In the present study, we comprehensively evaluated the antioxidant activities of 147 oral formulations of Japanese traditional herbal medicines (Kampo medicines), representing the entire panel of oral Kampo medicines listed in the Japanese National Health Insurance Drug List, using in vitro radical scavenging assays, including the 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity assay, the superoxide anion scavenging activity assay, and the oxygen radical absorption capacity assay. Three of the formulations tested, namely, Tsudosan, Daisaikoto, and Masiningan, showed the most potent in vitro antioxidant activities and were selected for further investigation of their intracellular and in vivo antioxidant effects. The results of the 2′,7′-dichlorodihydrofluorescin diacetate assay demonstrated that all three Kampo medicines significantly inhibited hydrogen peroxide-induced oxidative stress in human hepatocellular liver carcinoma HepG2 cells. In addition, Tsudosan significantly increased the serum biological antioxidant potential values when orally administrated to mice, indicating that it also had in vivo antioxidant activity. The potent antioxidant activity of Tsudosan may be one of the mechanisms closely correlated to its clinical usage against blood stasis.
