University of Groningen
The right enzyme with the right substrate can work wonders in the asymmetric synthesis of complex organic compounds. To an increasing extent, researchers at the University of Groningen (Netherlands) are succeeding in finding effective watches. In order to isolate water-soluble products, they make use of the LyovaporTM L-200 freeze-dryer.
Chemists working for the Chemical and Pharmaceutical Biology (CFB) research group have been making enzymes which are able to selective convert organic compounds and building in specific chemical structures on the right spot in the molecule.
Freeze Dryer, University of Groningen
As a result, complex syntheses for medicines can be achieved more efficiently, for example, in three stages rather than ten. Moreover, with the aid of enzymes, it is possible to obtain enantiomeric purities of 98% or more, which is essential to how a medicine works, because often only the R or S form is responsible for this. For many organic chemists with a conventional training, working with enzymes is an eye-opener and this is no less true for analyst Pieter Tepper. “In addition to the spectacular shortcuts in the synthesis pathways, it’s remarkable - especially seen from an organic perspective - that many of the reactions can be performed in buffered water, even the reductions.
There are practical benefits to this too. For example, freeze-drying provides an extremely efficient way to quickly isolate synthesized substances from the aqueous phase. „After extracting water using an organic solvent (not mixable with water), an oily product can be acquired, usually followed by evaporation from the organic solvent. If the product is soluble in water, freeze-drying offers a highly effective alternative. Often resulting rapidly in powdering and a solid product.“
The BÜCHI LyovaporTM L-200 has been used for freezedrying for a little over a year now. “Initially, the device - with a capacity of 6 kg (ice) - was on trial here, but we were happy with its performance. We decided to connect a 10 m3 per hour. Scroll pump which in terms of maintenance is more convenient than a centrifugal pump which contains oil.
Furthermore, we requested that the cooling unit was fitted with a transparent PMMA cover, so that we could see for ourselves the level of ice formation in the condensor. The device is operating on a 24/7 basis. In principle, we defrost and clean the device at the end of every week, thus preventing the formation of too much ice. If more ice forms than usual, at least we’re able to see this happening through the transparent inspection cover.”
Many Thanks to University of Groningen, Mr. Pieter Tepperfor the contribution and the picture material.