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Archive for the ‘Isotope effects’ Category

Mechanistic insights towards endoperoxide formation of artemisinin

Posted by naturalproductman on June 17, 2021

Artemisinin, one of the topics of the Nobel Prizes in Medicine in 2015, and its derivatives have been used to treat malaria. A new study published in the Journal of Natural Products finds that the endoperoxide formation of artemisinin from dihydroartemisinic acid, its biosynthetic precursor, undergoes a mixed mechanism. The study, from the lab of Francis Yoshimoto at UTSA, used regioselectively deuterated dihydroartemisinic acid isotopologues to measure competitive intermolecular kinetic isotope effects in the formation of artemisinin. The supporting information file is over 500 pages!

Cool!


Journal of Natural Products
paper

Posted in Antimalarial, Cyclic Peroxides, Diseases, Isotope effects, Malaria, Mass Spectrometry, Mechanistic, Peroxides, Terpenes | Leave a Comment »

The enamine is formed through an oxazolidinone intermediate

Posted by naturalproductman on February 4, 2016

When I think of organocatalysis, I usually think of a carbonyl compound forming an enamine intermediate, which in turn attacks an electrophile. The enamine is usually formed when the carbonyl compound reacts with a proline-derived catalyst. By using Gaussian and experimental KIE calculations, Matthew Vetticatt and co-workers at Binghamton University reported in JACS on the way that the enamine compound is formed: through an oxazolidinone intermediate.

oxazolidinone

JACS paper

 

A review article on determining the transition state structures based on KIEs.

Posted in Computational, Isotope effects, Mechanistic | Leave a Comment »

Syn-elimination

Posted by naturalproductman on May 14, 2014

Cristina de Meo and co-workers from Southern Illinois University reported in Organic Letters on a thiosialoside elimination of a thiophenol group, occuring by syn-elimination.

syn

OL paper

Posted in Half-chair, Isotope effects, Mechanistic | 1 Comment »

Half chair transition state

Posted by naturalproductman on February 17, 2012

Andrew Bennet and co-workers from Simon Fraser University have reported in JACS on a transition state study of a sialidase enzyme.

sialidase

JACS paper

Posted in Enzymes, Glucoside, Isotope effects, Mechanistic, Methodology, Proteins | Leave a Comment »

Ru-catalyzed hydroamidation

Posted by naturalproductman on April 26, 2011

Lukas Goossen and co-workers at TU Kaiserslautern have reported in JACS on a mechanistic investigation of a ruthenium catalyzed hydroamidation reaction of an alkyne.

ruthenium

JACS paper

Posted in Cascade Reactions, Isotope effects, Mechanistic, Methodology, Ruthenium, Transition Metal | Leave a Comment »