Copolymerization of l-lactide/trimethylene carbonate by organocatalysis: controlled synthesis of comb-like graft copolymers with side chains with different topologies

RSC Advances ◽  
2016 ◽  
Vol 6 (46) ◽  
pp. 40371-40382 ◽  
Author(s):  
Xuefei Leng ◽  
Zhiyong Wei ◽  
Yingying Ren ◽  
Yufei Bian ◽  
Qinyi Wang ◽  
...  

Synthesis of comb-like graft copolymers of lcP(LLA-co-TMC) from an organocatalyst/PB–OH system: including lcP(TMC-b-LLA), lcP(LLA-grad-TMC) and lcP(LLA-ran-TMC).

2021 ◽  
Vol 22 (4) ◽  
pp. 1572
Author(s):  
Constantin Tănase ◽  
Lucia Pintilie ◽  
Raluca Elena Tănase

In the total stereo-controlled synthesis of natural prostaglandins (PGs) and their structural analogs, a vast class of compounds and drugs, known as the lactones, are encountered in a few key steps to build the final molecule, as: δ-lactones, γ-lactones, and 1,9-, 1,11-, and 1,15-macrolactones. After the synthesis of 1,9-PGF2α and 1,15-PGF2α lactones, many 1,15-lactones of E2, E3, F2, F3, A2, and A3 were found in the marine mollusc Tethys fimbria and the quest for understanding their biological role stimulated the research on their synthesis. Then 1,9-, 1,11-, and 1,15-PG lactones of the drugs were synthesized as an alternative to the corresponding esters, and the first part of the paper describes the methods used for their synthesis. The efficient Corey procedure for the synthesis of prostaglandins uses the key δ-lactone and γ-lactone intermediates with three or four stereocenters on the cyclopentane fragment to link the PG side chains. The paper describes the most used procedures for the synthesis of the milestone δ-Corey-lactones and γ-Corey-lactones, their improvements, and some new promising methods, such as interesting, new stereo-controlled and catalyzed enantioselective reactions, and methods based on the chemical/enzymatic resolution of the compounds in different steps of the sequences. The many uses of δ-lactones not only for the synthesis of γ-lactones, but also for obtaining 9β-halogen-PGs and halogen-substituted cyclopentane intermediates, as synthons for new 9β-PG analogs and future applications, are also discussed.


e-Polymers ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Fatima Zohra Sebba ◽  
Seghier Ould Kada ◽  
Mohamed Benaicha ◽  
Nerjesse Nemiche

AbstractIn this study, 2-oxopropylmethacrylate-terminated poly(N-vinyl-2- pyrrolidone) is produced by cationic polymerization using HClO4 as an initiator. Termination (end capping) step is accomplished using 2- hydroxypropylmethacrylate (2HPMA) and the polymer product has different chain lengths of molecular weight averages ranging from 672 to 3049 g/mol. The study also synthesised amphipathic graft copolymers having hydrophobic poly(α- methylstyrene) as a backbone chain and hydrophilic poly(N-vinyl-2-pyrrolidone) (PVP) as side chains of various lengths. The copolymer synthesis was accomplished by free radical copolymerization of ω-oxopropylmethacrylate PVP in the presence of α-methyl styrene initiated with benzoyl peroxide. Measurements of the dynamic viscosity of the polymer solution (20% weight of macromonomers in ethanol) show that the viscosity is proportional to the average molecular weights M̅n . However, a reverse behaviour of the viscosity variation with regard to M̅n is observed for graft copolymer samples. The viscosity variation with respect to the graft copolymer mass must be due to steric effects, which are strongly pronounced in grafted copolymer chains. Appearance of the number of side chains attached to poly(α-methylstyrene) backbone reveals that the grafting reaction has occurred with good efficiency.


1986 ◽  
Vol 31 (7) ◽  
pp. 2303-2314 ◽  
Author(s):  
Takeaki Miyamoto ◽  
Shin-Ichi Takahashi ◽  
Sin-Ichi Tsuji ◽  
Hiraku Ito ◽  
Hiroshi Inagaki ◽  
...  

2018 ◽  
Vol 136 (6) ◽  
pp. 47051 ◽  
Author(s):  
Yongjun Guo ◽  
Rutong Song ◽  
Rusen Feng ◽  
Gang Dai ◽  
Yan Liang ◽  
...  
Keyword(s):  

2013 ◽  
Vol 51 (21) ◽  
pp. 1581-1591 ◽  
Author(s):  
Dirk Pfefferkorn ◽  
Martin Pulst ◽  
Toufik Naolou ◽  
Karsten Busse ◽  
Jens Balko ◽  
...  
Keyword(s):  

2019 ◽  
Vol 58 (39) ◽  
pp. 18468-18473 ◽  
Author(s):  
Baozheng Tian ◽  
Xianwei Zhang ◽  
Yuquan Cai ◽  
Hong Fan ◽  
Bo-Geng Li

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