Transaminase-Triggered Cascades for the Synthesis and Dynamic Kinetic Resolution of Chiral N-Heterocycles.

Biocatalysis is now a well-established branch of catalysis and the growing toolbox of natural, evolved and designer enzymes is enabling chemistry previously deemed inaccessible. However, most enzyme methodologies have been developed for functional group interconversions, such as the conversion of a ketone to an amine or alcohol, and do not result in the generation of significant 3D molecular complexity. The application of enzyme-triggered reaction cascade methodologies has the potential to transform simple substrates into complex sp3-rich molecules in one step.

Preparation of iminosugars from aminopolyols selective oxidation using galactose oxidase.

Minimally protected aminopolyols are novel substrates for the galactose oxidase variant F. Site-selective oxidation proceeds at the terminal primary alcohol, followed by spontaneous cyclisation to afford stable hemiaminal/hemiacetal anomers of the piperidine and azepane scaffolds, with isolated yields of up to 94%. Simultaneous deprotection and reduction occured readily to afford valuable and biologically relevant iminosugars.

Synthesis of the Hexahydropyrrolo-[3,2-c]-quinoline Core Structure and Strategies for Further Elaboration to Martinelline, Martinellic Acid, Incargranine B, and Seneciobipyrrolidine.

Natural products are rich sources of interesting scaffolds possessing a plethora of biological activity. With the isolation of the martinella alkaloids in 1995, namely martinelline and martinellic acid, the pyrrolo[3,2-c]quinoline scaffold was discovered. Since then, this scaffold has been found in two additional natural products, viz.

1,4-Dideoxy-1,4-imino-d-arabinitol (DAB) Analogues Possessing a Hydrazide Imide Moiety as Potent and Selective α-Mannosidase Inhibitors.

The synthesis of two polyhydroxylated pyrrolidines as 1,4-dideoxy-1,4-imino-d-arabinitol (DAB) analogues bearing a hydrazide moiety is described. The DAB analogues act as selective and potent inhibitors of α-mannosidase in the submicromolar concentration ranges ( values ranging from 0.23 to 1.

Synthesis of an Alleged Byproduct Precursor in Iodixanol Preparation.

, -Bis(2,3-dihydroxypropyl)-2,4,6-triiodo-5-(-(oxiran-2-ylmethyl)acetamido)isophthalamide (), the alleged precursor of several minor byproducts formed when the X-ray contrast agent iodixanol is synthesized from 5-acetamido- , -bis(2,3-dihydroxypropyl)-2,4,6-triiodoisophthalamide (), has been successfully prepared with an overall yield of 25%. Epoxide enabled the confirmation of its presence in the reaction mixture during the preparation of iodixanol when amide was used as the starting material.