Sunday, March 31, 2013

Coupling biocatalysis and click chemistry

DOI: 10.1039/C3CC38674K
1,2,3-triazoles: pharmacophores and ligands
Impressive driving force and selectivity.

Friday, March 29, 2013

Azide chemistry, energetic chemistry, hazardous chemistry, click chemistry

The spring-loaded energetic chemicals, azides and acetylenes, provide the necessary driving force of the "ideal" and non-stoppable triazole formation reaction, the most prominent of click chemistry concept. It is practiced in many academic groups worldwide, maybe in some pharmaceutical, biotech companies as well. Azides are often used to introduce amino groups in organic synthesis. Scanning any issue of JACS or JOC, one would see a bunch. 

In discovery chemistry where properties are sought, azide chemistry is good, click chemistry is wonderful.

When it comes to pharmaceutical or fine chemicals production, however, one tries to avoid azides as much as possbile, simply due to the very energetic nature of it. Azides are hazardous, no question about it - particularly when it come to large scale production. 
The avoidance however could add more steps of synthesis. Not good.

Double edged sword. Something has to give? 

A few companies have had success with many hazardous chemistries, up to metric ton scale. This competence separates them from competition. Extensive testing helps: impact & friction sensitivity, thermal stability, dust explosivity, reaction calorimetry. Stepwise scale-up helps: from lab to kilolab to pilot to plant. Engineering with prevention and in-case scenario in mind helps. Everyone's commitment and best training helps. Seamless work as a team helps. 

One day when a product by azide click chemistry is so successful and needs to be made by tons, it can be made.   

Sunday, March 24, 2013

Craig Hawker receives ACS Award in Polymer Chemistry

Feburary 2013 

Hawker, director of the Materials Research Laboratory at the University of California, Santa Barbara, has had an impact on the field of dendrimer chemistry, block copolymer, controlled free-radical polymerization - many of which are practical to be in commercial markets. 

He was one of the ground-breakers in convergent growth dendrimer synthesis. He was the first to introduce and apply click chemistry concept to dendrimer and material synthesis. See the 2004 key article by Hawker Group and Sharpless Group.