75567-13-4Relevant articles and documents
Differentiation of Contiguous Hydroxyl Groups by Regioselective Conversion of Acetonides into tert-Butyl Hydroxyalkyl Ethers
Cheng, Wen-Lung,Yeh, Sue-Min,Luh, Tien-Yau
, p. 5576 - 5577 (1993)
Treatment of the acetonides of simple contiguous diols or those derived from carbohydrates with the Grignard reagent yields regioselectively the corresponding hydroxyalkyl ether.
Cross-linked poly(N-vinylpyrrolidone)-titanium tetrachloride complex: A novel stable solid TiCl4 equivalent as a recyclable polymeric Lewis acid catalyst for regioselective ring-opening alcoholysis of epoxides
Rahmatpour, Ali,Sajjadinezhad, Seyed Mehrzad
, (2021/08/09)
Cross-linked poly(N-vinylpyrrolidone) resin beads were prepared as macromolecular ligand precursors by suspension copolymerization of N-vinyl-2-pyrrolidone and N,N′-methylenebisacrylamide (MBA) as a crosslinking agent in water. Subsequently, the resulting polymer carrier precursor was readily combined with titanium tetrachloride to form a stable polymeric coordination complex (PNVP/TiCl4), and this novel stable TiCl4 equivalent evaluated as a heterogeneous and reusable solid Lewis acid catalyst for the regio-and stereoselective nucleophilic ring opening of various epoxides with various alcohols to prepare β-alkoxy alcohols in excellent yields without generating any waste. The MBA-cross-linked PNVP and resultant catalyst were characterized by Fourier transform infrared spectroscopy (FT–IR), field-emission scanning electron microscope (FE–SEM), energy dispersive X-ray (EDX), inductively coupled plasma (ICP), and thermogravimetric analysis (TGA) techniques. Moreover, the catalyst is very stable, easily separated, and reused at least five times without significant loss of activity. In terms of scope, yields, the amount of catalyst used, and reaction time, the PNVP-TiCl4 complex catalyst is an improvement over previously reported heterogeneous catalysts for ring opening of epoxides methods. Further, the experimental outcome revealed that using the copolymer beads as carriers with a high percentage of crosslinking and the high mesh size leads had an adverse effect on the reaction rate.
MBA-cross-linked poly(N-vinyl-2-pyrrolidone)/ferric chloride macromolecular coordination complex as a novel and recyclable Lewis acid catalyst: Synthesis, characterization, and performance toward for regioselective ring-opening alcoholysis of epoxides
Rahmatpour, Ali,Zamani, Maryam
, (2021/09/30)
A novel macromolecular-metal coordination complex, MBA-cross-linked PNVP/FeCl3 material was fabricated by immobilization of water intolerant ferric chloride onto the porous cross-linked poly(N-vinyl-2-pyrrolidone) carrier beads as a macromolecular ligand or carrier which was prepared by suspension free-radical copolymerization of N-vinyl-2-pyrrolidone (NVP) and N,N′-methylene bis-acrylamide (MBA) as a crosslinking agent in water. The obtained PNVP/FeCl3 was characterized by UV/vis and FT-IR spectroscopies, TGA, FE-SEM, EDX, and ICP techniques. This heterogenized version of ferric chloride is a convenient and safe alternative to highly water intolerant ferric chloride. The catalytic performance of (PNVP/FeCl3) as an efficient and recyclable polymeric Lewis acid catalyst was appropriately probed in the regio-and stereoselective nucleophilic ring opening of various epoxides with various alcohols in excellent yields with TOF up to 182.48 h?1 without generating any waste. The activity data indicate that this heterogeneous catalyst is very active and could be easily recovered, and reused at least six times without appreciable loss of activity indicating its stability under experimental conditions.
Fiber-supported Fe(iii) complex catalyst in spinning basket reactor for cleaner ring-opening of epoxides with alcohols
Shi, Xian-Lei,Sun, Benyu,Hu, Qianqian,Chen, Yongju,Duan, Peigao
, p. 3573 - 3582 (2019/07/09)
Herein, a newly designed fiber-supported iron catalyst was successfully synthesized by rooting diamine ligands into the surface layer of commercially available polyacrylonitrile fiber and then utilizing the diamine groups to immobilize Fe(iii) ions for heterogeneous catalytic ring-opening reactions. The resulting materials were characterized and observed in detail by elemental analysis, mechanical properties, FTIR spectroscopy and morphology during both the preparation and the utilization processes. Moreover, the fiber catalyst was used in the spinning basket reactor-mediated ring-opening of various epoxides by a series of alcohols under mild reaction conditions, giving good to quantitative yields of the corresponding β-alkoxy alcohols. In addition, the fiber catalyst in the impellers of the agitation system was shown to be reusable multiple times without leaching of the Fe(iii) ions, and when stored on the shelf remained equally active for at least three months. Furthermore, the catalytic system was convenient and effective for scaling-up experiments and thereby has prospects in industrial applications.
