en 1 jacobsen s catalyst source own work by uploader author

N2 - Monensin A is a commercially important natural product isolated from Streptomyces cinnamonensins that is primarily employed to treat coccidiosis. Monensin A selectively complexes and transports sodium cations across lipid membranes and displays a variety of biological properties. In this study, we evaluated the Jacobsen catalyst as a cytochrome P450 biomimetic model to investigate the oxidation of monensin A. Mass spectrometry analysis of the products from these model systems revealed the formation of two products: 3-O-demethyl monensin A and 12-hydroxy monensin A, which are the same ones found in in vivo models. Monensin A and products obtained in biomimetic model were tested in a mitochondrial toxicity model assessment and an antimicrobial bioassay against Staphylococcus aureus, S. aureus methicillin-resistant, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Escherichia coli. Our results demonstrated the toxicological effects of monensin A in isolated rat liver mitochondria but not its products, showing that the metabolism of monensin A is a detoxification metabolism. In addition, the antimicrobial bioassay showed that monensin A and its products possessed activity against Gram-positive microorganisms but not for Gram-negative microorganisms. The results revealed the potential of application of this biomimetic chemical model in the synthesis of drug metabolites, providing metabolites for biological tests and other purposes.

and the very complicated-looking Jacobsen catalyst (not pictured

T1 - Jacobsen Catalyst as a Cytochrome P450 Biomimetic Model for the Metabolism of Monensin A

reported by katsuki using derivatives of the jacobsen catalyst

Discussions of the mechanism of the oxygen transfer to the double bond have led to controversy. Depending on the substrate and additives, the formation of side products with stereochemistry points to a radical mechanism, whereas alkyl-substituted olefins stereoselectively give only products via a concerted mechanism. The suggested formation of manganaoxetanes receives support from calculations on a theoretical level, and from experiments reported by Katsuki using derivatives of the Jacobsen catalyst.

Best Jacobsen Catalyst: R = tBu

Jacobsen's catalyst,N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediaminomanganese(III)chloride, is a popular reagent for the enantioselective epoxidation ofalkenes. This reagent is successfully prepared in three steps bybeginning organic chemistry students. A mixture of1,2-diaminocyclohexane isomers is purified and resolved bycrystallization (and recrystallization) with L-tartaric acid; a diimineis formed between the resolved trans-1,2-diaminocyclohexane and3,5-di-tert-butyl-2-hydroxybenzaldehyde to produce the Jacobsen ligand;and finally Jacobsen's catalyst is prepared from the ligand by treatmentwith manganese(II) acetate followed by oxidation with air. The studentsthen use their Jacobsen catalyst to enantioselectively epoxidize one ofthe following alkenes: 1,2-dihydronaphthalene, styrene, ora-methylstyrene. After purifying their epoxides by flash chromatography,students determine the enantiopurity by GC using a chiral column. Inthis series of experiments students utilize a wide variety of laboratorytechniques: running a reaction at reflux, aqueous workup with aseparatory funnel, recrystallization, flash chromatography, TLC,polarimetry, IR and NMR spectroscopy, and chiral GC analysis. These labsalso reinforce many important concepts related to chirality,stereochemistry, and optical activity.

conclusion final product of this Jacobsen catalyzed epoxidation was a mixture of
carried out. In order for the Jacobsen catalyzed epoxidation to produce highly

Jacobsen epoxidation - Wikipedia, the free encyclopedia

Control over the stereochemistry of a desired product in chemical synthesis is an ongoing problem. Specifically, the selectivity of chiral molecules has been the most challenging problem in organic synthesis. Often, to overcome this problem, chiral catalysts are employed to induce preference for one chiral product over another. One catalyst, known as the Jacobsen catalyst, has been utilized for the enantioselective oxidative conversion of alkenes to epoxides in the presence of a large amount of an oxidizer.1

we evaluated the Jacobsen catalyst as a cytochrome P450 biomimetic model ..

Jacobsen’s catalyst, the styrene and ..

Discussions of the mechanism of the oxygen transfer to the double bond have led to controversy. Depending on the substrate and additives, the formation of side products with stereochemistry points to a radical mechanism, whereas alkyl-substituted olefins stereoselectively give only products via a concerted mechanism. The suggested formation of manganaoxetanes receives support from calculations on a theoretical level, and from experiments reported by Katsuki using derivatives of the Jacobsen catalyst.

OSHA Vacated PELs: (S,S)-Jacobsen catalyst, 98%: No OSHA Vacated PELs are listed for this chemical

The Hydrolytic Kinetic Resolution – Jacobsen’s Catalyst

Discussions of the mechanism of the oxygen transfer to the double bond have led to controversy. Depending on the substrate and additives, the formation of side products with stereochemistry points to a radical mechanism, whereas alkyl-substituted olefins stereoselectively give only products via a concerted mechanism. The suggested formation of manganaoxetanes receives support from calculations on a theoretical level, and from experiments reported by Katsuki using derivatives of the Jacobsen catalyst.