Topic
Morpholine
About: Morpholine is a research topic. Over the lifetime, 5411 publications have been published within this topic receiving 51063 citations. The topic is also known as: diethylene imidoxide & diethylene oximide.
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TL;DR: The preliminary mechanistic studies provided some insight regarding the key events in the proposed catalytic cycle, including beta-hydride elimination of an amido rhodium complex and carbometalation of the resulting imine.
Abstract: The development of a new chemical transformation, namely oxidative C-arylation of saturated (NH)-heterocycles, is described. This reaction combines dehydrogenation and arylation in one process, leading to cross-coupling of (NH)-heterocycles and haloarenes. Typical reaction conditions involve heating the reaction partners in anhydrous dioxane at 120−150 °C in the presence of RhCl(CO)[P(Fur)3]2 as the catalyst and Cs2CO3 as the base. Addition of tert-butylethylene as the hydrogen acceptor increases the chemical yield by diminishing the dehalogenation pathway. This method demonstrated a good substrate scope, allowing for cross-coupling of a variety of (NH)-heterocycles (e.g., pyrrolidine, piperidine, piperazine, morpholine) and halo(hetero)arenes to afford valuable heterocyclic products in one step. The preliminary mechanistic studies provided some insight regarding the key events in the proposed catalytic cycle, including β-hydride elimination of an amido rhodium complex and carbometalation of the resulting...
34 citations
TL;DR: The addition of (pentafluoroethyl)- and (heptafluoropropyl)lithium to various acyl derivatives was studied to provide inhibitors for various lipolytic enzymes, including phospholipase A2.
Abstract: The addition of (pentafluoroethyl)- and (heptafluoropropyl)lithium to various acyl derivatives was studied. Weinreb and morpholine amides led to polyfluoro ketones in high to quantitative yields in short reaction times. Derivatives of 2-fluorocarboxylic acids may produce 1,1,1,2,2,4-hexafluoro ketones and 1,1,1,2,2,3,3,5-octafluoro ketones. The methodology can provide inhibitors for various lipolytic enzymes, including phospholipase A2.
34 citations
34 citations
TL;DR: A broad variety of chiral C/N-functionalized morpholine alcohols sharing a common structural motif in the 3-(hydroxymethyl)morpholine 6 were prepared from enantiomerically pure serine for the purpose of studying their catalytic ligand properties as discussed by the authors.
Abstract: A broad variety of chiral C/N-functionalized morpholine alcohols sharing a common structural motif in the 3-(hydroxymethyl)morpholine 6 were prepared from enantiomerically pure serine for the purpose of studying their catalytic ligand properties. The asymmetric addition of diethylzinc to benzaldehyde in the presence of 10 mol % of chiral C/N-functionalized morpholine alcohols gave 1-phenyl-1-propanol in 59–81% yield with 10–30% ee. The addition of 10 mol % of n -butyl lithium to the reaction mixture resulted in a significant enhancement of the stereoselectivity in the case of ligands bearing the two geminal phenyl substituents on the backbone. In the presence of n -butyl lithium and using ( S )-3-(hydroxydiphenylmethyl)morpholine ( S )- 19 as the chiral promoter, ( S )-1-phenyl-1-propanol was obtained in 81% yield with 76% ee. The geminal diphenyl-class of morpholine ligands was examined for the diethylzinc addition to four different aldehydes in the presence of n -butyl lithium. ( S )- N -Benzyl-3-(hydroxydiphenylmethyl)morpholine ( S )- 27 was found to be most enantioselective in the case of 4-methoxybenzaldehyde to give ( R )-alcohol in 87% yield with 80% ee. Catalysts ( S )- 19 and its N -methyl derivative ( S )- 26 gave alcohols with an ( S )-absolute configuration while the N-benzylated derivative ( S )- 27 gave the opposite enantiomeric products. The tentative transition state models to account for the observed product stereoselectivity with morpholine ligands holding the geminal diphenyl group on the β-amino alcohol segment are proposed.
34 citations
TL;DR: The experiments were conducted using morpholine as a representative secondary amine as a potential CO₂ capture solvent with 100 ppm standard NO₁ gas to better understand the nitrosamine reaction pathways under scrubber and stripper conditions and the roles of nitrite and nitrite were probed.
Abstract: The amine assisted CO2 capture process from coal fired power plants strives for the determination of degradation components and its consequences. Among them, nitrosamine formation and their emissions are of particular concern due to their environmental and health effects. The experiments were conducted using morpholine as a representative secondary amine as a potential CO2 capture solvent with 100 ppm standard NO2 gas to better understand the nitrosamine reaction pathways under scrubber and stripper conditions. The role of nitrite in the nitrosation reaction was probed at elevated temperatures. The effects of different concentrations of nitrite on morpholine were evaluated. Formation rate, decomposition rates, activation energy, and the possible reaction pathways are elaborated. Thermal stability tests at 135 °C indicated the decomposition of nitrosamines at the rate of 1 μg/(g h) with activation energy of 131 kJ/mol. The activation energy for the reaction of morpholine with sodium nitrite was found as 10...
34 citations