57079-16-0Relevant academic research and scientific papers
Thermally reversible crosslinked polyethylene using Diels-Alder reaction in molten state
Magana, Sylvain,Zerroukhi, Amar,Jegat, Corinne,Mignard, Nathalie
experimental part, p. 442 - 448 (2011/12/16)
Thermally reversible crosslinked polyethylene was prepared by Diels-Alder (DA) and retro Diels-Alder (rDA) reaction. Maleimide/furan adduct was used as crosslinking agent. Dienophile named 11-maleimido-undecanoic acid was first synthesized and between this dienophile and commercial 3-(2-furyl) propanoic acid, the DA reaction was studied to determine DA and rDA reactions temperatures in the solid state. Then, an original modification method was employed to graft the two molecules onto the Lotader poly(ethylene-co-glycidyl methacrylate) in one step procedure. The DA and rDA reactions between diene and dienophile grafted moieties are followed by FT-IR analysis on a thin film. Readily polymer network is synthesized and the cycle of DA and retro-DA reactions is repeatable with no significant polymer degradation.
Design, synthesis, and biochemical evaluation of N-substituted maleimides as inhibitors of prostaglandin endoperoxide synthases
Kalgutkar, Amit S.,Crews, Brenda C.,Marnett, Lawrence J.
, p. 1692 - 1703 (2007/10/03)
N-(Carboxyalkyl)maleimides are rapid as well as time-dependent inhibitors of prostaglandin endoperoxide synthase (PGHS). The corresponding N- alkylmaleimides were only time-dependent inactivators of PGHS, suggesting that the carboxylate is critical for rapid inhibition. Several N-substituted maleimide analogs containing structural features similar to those of the nonsteroidal anti-inflammatory drug aspirin were synthesized and evaluated as inhibitors of PGHS. Most of the aspirin-like maleimides inactivated the cyclooxygenase activity of purified ovine PGHS-1 in a time- and concentration-dependent manner similar to that of aspirin. The peroxidase activity of PGHS was also inactivated by the maleimide analogs. The cyclooxygenase activity of the inducible isozyme, i.e., PGHS-2, was also inhibited by these compounds. The corresponding succinimide analog of N-5- maleimido-2-acetoxy-1-benzoic acid did not inhibit either enzyme activity, suggesting that inactivation was due to covalent modification of the protein. The mechanism of inhibition of PGHS-1 by N-(carboxyheptyl)maleimide was investigated. Incubation of apoPGHS-1 with 2 equiv of N-(carboxyheptyl)[3,4- 14C]maleimide led to the incorporation of radioactivity in the protein, but no adduct was detected by reversed-phase HPLC, suggesting that it was unstable to the chromatographic conditions. Furthermore, hematin- reconstituted PGHS-1, which was rapidly inhibited by N- (carboxyheptyl)maleimide, displayed spontaneous regeneration of about 50% of the cyclooxygenase and peroxidase activities, suggesting that the adduct responsible for the inhibition breaks down to regenerate active enzyme. ApoPGHS-1, inhibited by N-(carboxyheptyl)maleimide, did not display regeneration of enzyme activity, but addition of hematin to the inhibited apoenzyme led to spontaneous recovery of about 50% of cyclooxygenase activity. These results suggest that addition of heme leads to a conformational change in the protein which increases the susceptibility of the adduct toward hydrolytic cleavage. ApoPGHS-1, pretreated with N(carboxyheptyl)maleimide, was resistant to trypsin cleavage, suggesting that the carboxylate functionality of the maleimide binds in the cyclooxygenase channel. A model for the interaction of N-(carboxyheptyl)maleimide in the cyclooxygenase active site is proposed.
