108212-53-9Relevant academic research and scientific papers
Chitosan grafted with a heteropolyanion-based ionic liquid as an effective and reusable catalyst for acetalization
Zhang, Wei-Hong,Liu, Shan-Shan,Liu, Ping,Xu, Jie,Xue, Bing,Wei, Xian-Yong,Li, Yong-Xin
, p. 41404 - 41409 (2016/05/19)
Chitosan immobilized with an acidic ionic liquid (CS-VImPS-PW) was fabricated via a radical addition reaction of N-vinylimidazoliumpropane sulfonate and chitosan, followed by acidification with a heteropolyacid. It was characterized by a Fourier transform infrared spectrometer, solid-state 13C nuclear magnetic resonance spectrometer, thermogravimetric analyzer, elemental analyzer, and Hammett indicator. Some acetalization reactions were investigated to evaluate the catalytic activity of CS-VImPS-PW. The results show that CS-VImPS-PW is highly active for the acetalization reactions in high acetal yields ranging from 83.2 to 96.2% and can be reused 8 times without noticeable loss of activity.
Synthesis and biological evaluation of new 4β-anilino-4′-O- demethyl-4-desoxypodophyllotoxin derivatives as potential antitumor agents
Wang, Li,Yang, Fenyan,Yang, Xiaochun,Guan, Xianghong,Hu, Chunqi,Liu, Tao,He, Qiaojun,Yang, Bo,Hu, Yongzhou
scheme or table, p. 285 - 296 (2011/03/17)
A series of new 4β-anilino-4′-O-demethyl-4-desoxypodophyllotoxin derivatives were prepared and evaluated for their cytotoxicities against four human cancer cell lines including KB, KB/VCR, A549 and 95D. Most compounds showed better growth-inhibition activities against tested cell lines than that of etoposide (VP-16). Preliminary structure-activity relationships (SARs) were concluded and it indicated that the side chains substituted at 4β position of podophyllotoxin significantly influenced the cytotoxic activity, especially for the drug resistance profile. In vivo studies of compound 26c on highly metastatic human lung cancer xenograft in nude mice showed that it can significantly inhibit tumor growth with administrating by oral route.
Indium metal as a reducing agent in organic synthesis
Pitts,Harrison,Moody
, p. 955 - 977 (2007/10/03)
The low first ionisation potential (5.8 eV) of indium coupled with its stability towards air and water, suggest that this metallic element should be a useful reducing agent for organic substrates. The use of indium metal for the reduction of C=N bonds in imines, the heterocyclic ring in benzo-fused nitrogen heterocycles, of oximes, nitro compounds and conjugated alkenes and the removal of 4-nitrobenzyl protecting groups is described. Thus the heterocyclic ring in quinolines, isoquinolines and quinoxalines is selectively reduced using indium metal in aqueous ethanolic ammonium chloride. Treatment of a range of aromatic nitro compounds under similar conditions results in selective reduction of the nitro groups; ester, nitrile, amide and halide substituents are unaffected. Likewise indium in aqueous ethanolic ammonium chloride is an effective method for the deprotection of 4-nitrobenzyl ethers and esters. Indium is also an effective reducing agent under non-aqueous conditions and α-oximino carbonyl compounds can be selectively reduced to the corresponding N-protected amine with indium powder, acetic acid in THF in the presence of acetic anhydride or di-tert-butyl dicarbonate. Conjugated alkenes are also reduced by indium in THF-acetic acid.
4-Pivaloylaminobenzyl ether, a new temporary protection for hydroxyl functions
Fukase, Koichi,Yoshimura, Takuya,Hashida, Manabu,Kusumoto, Shoichi
, p. 4019 - 4022 (2007/10/02)
4-Pivaloylaminobenzyl (PAB) group is a new benzyl-type protecting group which can be introduced either by initial introduction of 4-nitrobenzyl group followed by reduction and N-acylation or by the reaction of a hydroxyl compound with the corresponding halogenide or trichloroacetimidate. PAB ethers have higher acid stability than 4-methoxybenzyl ethers but are readily cleaved with DDQ in a manner similar to the latter.
