离子液体,即[甜菜碱][H 2 PO 4 ],被发现是无溶剂条件下xanthen-9-ol与不同亲核试剂直接取代反应的有效催化剂。该催化体系易于操作,后续后处理程序简单,离子液体催化剂可在高催化活性水平下重复使用至少五个循环。此外,离子液体制备简单,原料廉价,生物相容性好。因此,我们的研究提出了一种有趣且可持续的直接替代酒精的方案。
Oxidation of xanthenes with manganese(III) acetate in the presence of active methylene compounds such as 1,3-dicarbonyl compounds, malononitrile derivatives, acetone, and nitromethane selectively gives 9-substituted xanthene derivatives in good yields. A similar oxidation of thioxanthene also yields 2-(9-thioxanthenyl)-1,3-dicarbonyl compounds in 57-91% yields. The obtained 2-(9-xanthenyl)-1,3-dicarbonyl compounds are readily converted to 2-(9-xanthenylidene)-1,3-dicarbonyl derivatives using manganese(III) complexes or 2,3-dichloro-5, 6-dicyano-1,4-benzoquinone. The mechanisms for the formation of 9-substituted xanthenes are discussed on the basis of the reaction of intermediates, the electron-donating substituent effect on the xanthene ring system, effect of additives, and comparison with a reaction of radical-trapping reagents.
Reaction of Thiaxanthydrol With Compounds Containing Active Hydrogen<sup>1</sup>
作者:EUGENE SAWICKI、VINCENT T. OLIVERIO
DOI:10.1021/jo01108a009
日期:1956.2
Biocompatible ionic liquid [Betaine][H<sub>2</sub>PO<sub>4</sub>] as a reusable catalyst for the substitution of xanthen-9-ol under solvent-free conditions
作者:Anlian Zhu、Tong Wang、Wanlu Feng、Jianji Wang、Lingjun Li
DOI:10.1039/d0ra05374k
日期:——
An ionicliquid, namely [Betaine][H2PO4], was found to be an efficientcatalyst for the direct substitution reaction of xanthen-9-ol with different nucleophiles under solvent-free conditions. This catalytic system is easy to be operated and the following work-up procedure is simple, with the ionicliquidcatalystreusable for at least five cycles at a high catalytic activity level. In addition, the
离子液体,即[甜菜碱][H 2 PO 4 ],被发现是无溶剂条件下xanthen-9-ol与不同亲核试剂直接取代反应的有效催化剂。该催化体系易于操作,后续后处理程序简单,离子液体催化剂可在高催化活性水平下重复使用至少五个循环。此外,离子液体制备简单,原料廉价,生物相容性好。因此,我们的研究提出了一种有趣且可持续的直接替代酒精的方案。
Determination of Thermodynamic Affinities of Various Polar Olefins as Hydride, Hydrogen Atom, and Electron Acceptors in Acetonitrile
thermodynamic affinities of the hydrogen adducts of the polar olefins (XH•) obtaining electrons in acetonitrile were determined using titration calorimetry and electrochemical methods. The pure C═C π-bond heterolytic and homolytic dissociation energies of the polar olefins (X) in acetonitrile and the pure C═C π-bond homolytic dissociation energies of the radical anions of the polar olefins (X•–) in acetonitrile