200058-21-5Relevant academic research and scientific papers
General Strategy for Improving the Quantum Efficiency of Photoredox Hydroamidation Catalysis
Ruccolo, Serge,Qin, Yangzhong,Schnedermann, Christoph,Nocera, Daniel G.
, p. 14926 - 14937 (2018)
The quantum efficiency in photoredox catalysis is the crucial determinant of energy intensity and, thus, is intrinsically tied to the sustainability of the overall process. Here, we track the formation of different transient species of a catalytic photoredox hydroamidation reaction initiated by the reaction of an Ir(III) photoexcited complex with 2-cyclohexen-1-yl(4-bromophenyl)carbamate. We find that the back reaction between the amidyl radical and Ir(II) photoproducts generated from the quenching reaction leads to a low quantum efficiency of the system. Using transient absorption spectroscopy, all of the rate constants for productive and nonproductive pathways of the catalytic cycle have been determined, enabling us to establish a kinetically competent equilibrium involving the crucial amidyl radical intermediate that minimizes its back reaction with the Ir(II) photoproduct. This strategy of using an off-pathway equilibrium allows us to improve the overall quantum efficiency of the reaction by a factor of 4. Our results highlight the benefits from targeting the back-electron transfer reactions of photoredox catalytic cycles to lead to improved energy efficiency and accordingly improved sustainability and cost benefits of photoredox synthetic methods.
Synthesis of (-)-oseltamivir by using a microreactor in the curtius rearrangement
Ishikawa, Hayato,Bondzic, Bojan P.,Hayashi, Yujiro
experimental part, p. 6020 - 6031 (2011/12/15)
A microflow reaction of the Curtius rearrangement by using trimethylsilyl azide as an azide source, followed by trapping of the generated isocyanate with a nucleophile was established, which is safe, inexpensive, and suitable for large-scale synthesis. By this flow reaction in the Curtius rearrangement and recrystallization of the late-stage acetamide intermediate the third-generation synthesis of (-)-Oseltamivir has been established, which is efficient, practical, and safe. A safe and efficient total synthesis of (-)-Oseltamivir has been developed by using the Curtius rearrangement with a microflow system, which avoids the isolation of a hazardous and potentially explosive intermediate. In addition, the product, possessing an acetamide group, was easily purified by recrystallization. Thus, this procedure can be scaled up as an industrial process.
MONOACYLGLYCEROL LIPASE INHIBITORS FOR MODULATION OF CANNABINOID ACTIVITY
-
Page/Page column 104-105, (2009/05/28)
Disclosed are compounds and compositions that inhibit the action of monoacylglycerol lipase (MGL) and fatty acid amide hydrolase (FAAH), methods of inhibiting MGL and FAAH, methods of modulating cannabinoid receptors, and methods of treating various disorders related to the modulation of cannabinoid receptors.
FATTY ACID AMIDE HYDROLASE INHIBITORS
-
Page/Page column 64; 66, (2008/06/13)
Disclosed are compounds of formula R-X-Y that may be used to inhibit the action of fatty acid amide hydrolase (FAAH). Inhibition of fatty acid amide hydrolase (FAAH) will slow the normal degradation and inactivation of endogenous cannabinoid ligands by FAAH hydrolysis and allow higher levels of those endogenous cannabinergic ligands to remain present. These higher levels of endocannabinoid ligands provide increased stimulation of the cannabinoid CBl and CB2 receptors and produce physiological effects related to the activation of the cannabinoid receptors. They will also enhance the effects of other exogenous cannabinergic ligands and allow them to produce their effects at lower concentrations as compared to systems in which fatty acid amide hydrolase (FAAH) action is hot inhibited. Thus, a compound that inhibits the inactivation of endogenous cannabinoid ligands by fatty acid amide hydrolase (FAAH) may increase the levels of endocannabinoids and, thus, enhance the activation of cannabinoid receptors. Thus, the compound may not directly modulate the cannabinoid receptors but has the effect of indirectly stimulating the cannabinoid receptors by increasing the levels of endocannabinoid ligands. It may also enhance the effects and duration of action of other exogenous cannabinergic ligands that are administered in order to elicit a cannabinergic response.
