4208-64-4Relevant articles and documents
A novel route to stereoselective synthesis of (4R,5S)-O- acetylosmundalactone and (4S,5R)-O-acetylosmundalactone
Yonghong, Gan,Fangning, Zhang,Xinfu, Pan
, p. 488 - 489 (1999)
A route has been developed for the enantioselective synthesis of (4R,5S)-O-acetylosmundalactone 1 and (4S,5R)-O-acetylosmundalactone 2 by using sharpless kinetic resolution of the racemic 1-(2-furyl)ethanol 6 as a key step.
Cationic Ru complexes anchored on POM via non-covalent interaction towards efficient transfer hydrogenation catalysis
Chen, Manyu,Cui, Kai,Hou, Zhenshan,Peng, Qingpo,Wang, Jiajia,Wei, Xinjia,Zhao, Xiuge
, (2021/12/22)
The ionic materials consisting of cationic Ru complexes and Wells-Dawson polyoxometalate anion (POM, K6P2W18O62) have been constructed via a non-covalent interaction. The as-synthesized catalysts have been characterized thoroughly by NMR, XRD, FESEM, and FT-IR, etc. The characterization suggested that a hydrogen bond interaction occurred between the proton of the amine ligand in the cationic Ru complexes and the oxygen atom of the POM anion. The hydrogen bond played an important role in enhancing catalytic activity for the transfer hydrogenation of methyl levulinate (ML) to γ-valerolactone (GVL) under very mild conditions. Especially, the transfer hydrogenation reaction proceeded via a heterogeneous catalysis approach and the heterogenized catalysts even afforded much better catalytic performance than homogeneous analogs. Notably, the catalysts can be recycled without an obvious loss of activity, and further extended to highly selective transfer hydrogenation of α,β-unsaturated ketones and aldehydes, etc. into the corresponding α,β-unsaturated alcohols without any base external additives. The high catalytic performance of these anchored catalysts was highly related to the hydrogen bond interaction and the basicity of the polyanion. The obtained knowledge from this work could lead us to a new catalysis concept of tethering active homogeneous complexes for constructing highly active anchored Ru complex catalysts for hydrogenation reaction.
2, 4, 5-Trideoxyhexopyranosides Derivatives of 4’-Demethylepipodophyllotoxin: De novo Synthesis and Anticancer Activity
Cai, Rui,Li, Yu,Lu, Yapeng,Zhao, Yu,Zhu, Li
, p. 130 - 139 (2022/03/09)
Background: Podophyllotoxin is a natural lignan which possesses anticancer and antiviral activities. Etoposide and teniposide are semisynthetic glycoside derivatives of podophyllotoxin and are increasingly used in cancer medicine. Objective: The present work aimed to design and synthesize a series of 2, 4, 5-trideoxyhexopyrano-sides derivatives of 4’-demethylepipodophyllotoxin as novel anticancer agents. Methods: A divergent de novo synthesis of 2, 4, 5-trideoxyhexopyranosides derivatives of 4’-demethylepipodophyllotoxin has been established via palladium-catalyzed glycosylation. The abili-ties of synthesized glycosides to inhibit the growth of A549, HepG2, SH-SY5Y, KB/VCR and HeLa cancer cells were investigated by MTT assay. Flow cytometric analysis of cell cycle with propidium iodide DNA staining was employed to observe the effect of compound 5b on cancer cell cycle. Results: Twelve D and L monosaccharide derivatives 5a-5l have been efficiently synthesized in three steps from various pyranone building blocks employing de novo glycosylation strategy. D-monosaccharide 5b showed the highest cytotoxicity on five cancer cell lines with the IC50 values ranging from 0.9 to 6.7 μM. It caused HepG2 cycle arrest at G2/M phase in a concentration-dependent manner. Conclusion: The present work leads to the development of novel 2, 4, 5-trideoxyhexopyranosides derivatives of 4’-demethylepipodophyllotoxin. The biological results suggest that the replacement of the glucosyl moiety of etoposide with 2, 4, 5-trideoxyhexopyranosyl is favorable to their cytotoxic-ity. D-monosaccharide 5b was observed to cause HepG2 cycle arrest at the G2/M phase in a concen-tration-dependent manner.
Manganese-Catalyzed Hydrogenation of Ketones under Mild and Base-free Conditions
Brünig, Julian,Kirchner, Karl,Veiros, Luis F.,Weber, Stefan
supporting information, p. 1388 - 1394 (2021/05/31)
In this paper, several Mn(I) complexes were applied as catalysts for the homogeneous hydrogenation of ketones. The most active precatalyst is the bench-stable alkyl bisphosphine Mn(I) complex fac-[Mn(dippe) (CO)3(CH2CH2CH3)]. The reaction proceeds at room temperature under base-free conditions with a catalyst loading of 3 mol % and a hydrogen pressure of 10 bar. A temperature-dependent selectivity for the reduction of α,β-unsaturated carbonyls was observed. At room temperature, the carbonyl group was selectively hydrogenated, while the C=C bond stayed intact. At 60 °C, fully saturated systems were obtained. A plausible mechanism based on DFT calculations which involves an inner-sphere hydride transfer is proposed.
