Organic reactions are generally inefficient, which means that crude reaction mixtures require work-up and purification to remove by-products and unreacted starting materials and/or catalysts. The goal in pharmaceutical research is to isolate the target compound with required purity and yield to be able to progress to the next synthetic sequence or biological testing with confidence. But the process of purification is viewed by synthetic chemists as a ‘means-to-an-end’ and the more rapidly and reliably the purification step can be performed the better. Easy enough to state, but hard to achieve when you need to be certain of purity and yield in a single, rapid purification attempt. As we will see here, flash column chromatography can help you achieve this.
First, join me on a flashback to my past as a discovery chemist just fresh out of grad school and eager to make a difference in pharmaceutical research. I was advised by my boss to model my behavior after a colleague and labmate with a reputation of being highly productive and successful. I was also informed that ‘chemist productivity’ was measured by 1) the number of compounds (of sufficient quantity and quality) he/she registered in the company’s database and 2) meeting project milestones.
Chemistry, by its very nature, involves the use of chemicals that can be harmful, toxic and potentially damaging to the environment, which means that drug discovery currently has a large and expensive environmental footprint. However, all is not lost. With a few small steps it is possible to make a big change to the impact that drug discovery has on our world. Let’s look at ways we can reduce the environmental impact of chemical processing and flash chromatography. This involves using green chemistry applications in the purification workflow to find a solution that reduces chemical waste to make it good for both the chemist and the environment.
Chromatographic purification methods such as flash chromatography can have a high environmental impact since they typically involve large quantities of harmful or toxic solvents run at high flow rates. In many laboratories the cost of procuring and then disposing of these solvents can be a major part of the overall cost of projects. For the chemist, trying to reduce the environmental impact of small molecule synthesis is part of being a good global citizen. Here are three strategies that greatly reduce the environmental impact of flash purifications. It can also save money in the long run by reducing the cost of chemical waste disposal.