Category Archives: Alkaloids

Matrine isomerism

An investigation on matrine , a tetracyclic bis-quinolizidine alkaloid from the Sephora plants, was published in January 2021 in Journal  of Organic Chemistry. The molecule showed two (trans and cis) isomers in the gas-phase, confirming conformational rearrangements in matrine alkaloids. Matrine alkaloids have four stereogenic carbon centers, producing a large family of 16 stereoisomers in 8 enantiomeric pairs.


Pseudopelletierine in CEJ

An article on the methyl inversion and structure of the tropane alkaloid pseudopelletierine has been published in Chemistry: A European Journal. The article  includes extensive (multi-isotopologue) rotational data, together with theoretical calculations on the equilibrium structure of the molecule, in collaboration with Jean Demaison and Natalja Vogt.

In the figure below the inversion potential of the methyl group in pseudopelletierine and the pomegranate tree, where this alkaloid can be found.

 


Sparteine in PCCP

The dimer sparteine-water has been highlighted as cover of PCCP and part of “2017 PCCP HOT Articles“. Sparteine is a tetracyclic quinolizidine alkaloid used in assymetric synthesis, with two trans and cis conformations. We investigated whether addition of a water molecule flips the molecule by formation of a double hydrogen bond to the cis diamine used in metal complexation. Kinetic reasons explain that the cluster retains the monomer trans conformation.

In the cover picture below the conversion between the observed trans isomer (above) and the alternative cis isomer (below).