News

In our previous application note (No. 41) we reported on a green and efficient photochemical route to the reduction of 3-nitro-acetophenone to 3-amino-acetophenone. Challenged to show the broad applicability of the photochemical reduction using the low cost and green TiO2 photo catalyst we set out to extend this work to optimize the reduction of 3 further Nitro compounds. The compounds chosen exhibit a range of different reactivity, one compound was further chosen as a ‘real-world’ example, 4-(2-fluoro-4-nitrophenyl) morpholine being a key intermediate used in the synthesis of the oxazolidinone antibiotic Linezolid (Pfizer brand name ZYVOX®)

This application note demonstrates a green photochemical route to the reduction of Nitro compounds. The powerful combination of Vapourtec’s V-3 pump and the UV-150 Photochemical reactor is utilized to deliver the photo catalyst as a slurry and provide precise control over the continuous flow photochemical reaction, even with the short reaction times of less than 1 minute. The TiO2 photo catalyst is safe, cheap and simply removed by filtration. There is also a fascinating comparison of the performance of three different 365 nm light sources; filtered mercury lamp, LED Gen-1 and LED Gen-2. The Gen-2 LED achieves comparable throughput of the mercury lamp while consuming <50% of the power.

Researchers at the University of Southampton and GlaxoSmithKline have used Vapourtec’s R-Series flow chemistry system to synthesise Ketones in Flow by thermal sigmatropic rearrangement of alkoxyalkynes, and their trapping with amines or alcohols to provide amides and esters.